Ok ,let's start with a short, very short history of pottery making in the UK and that means England, Scotland, Wales and Northern Ireland and, for the purpose of this excercise only ... to include the republic of Ireland.

We are going to forget the Romans, the Celts, The Anglo Saxons, the Danes and the Norsemen all of whom arrived here and settled. For the practical purposes of the china we shall see on Ebay let's leap to the mid 18th century.   

But first, lets start off by understanding what is porcelain and what is pottery.

Porcelain is fine, thin, hard, strong transluscent china - often labeled "Bone China" and so thin you can hold it to a light bub and see through it. My golden rule is if I can't see a light bulb through it;   its not  porcelain

Pottery - is everything thing else. Thats Wedgwood's  Jasperware,  Majolica, Moorcroft, Earthen ware, Ironstone china, Terra Cotta and all that amorphous pile of dinnerware and transferware from hundreds of potters etc etc. It can and often is fine pieces but it will lack that essential translucancy.

The Europeans had been seeing a lot of the fine porcelain coming out of China and there was nothing here to match it. It was like the jet aircraft when only the British made them - if you wanted to fly  jet you had to fly British well, if you wanted fine porcelain then it had to be Chinese. The British and other Europeans were determined that whatever the Chinese could do they could do better. Meissen in Germany found answers and this was followed by a number of English potters notably a William Cookworthy who found the secret almost by accident using the finest  English China clay from Cornwall. He set up a factory in Plymouth which them moved to Bristol. 

Early pottery -  17th century - carried no bottom marks, invariably it was identied by its decoration , its colours and its material. But there was some potters who blazonned there name across the front of there wares - Ralph Toft being one such maker who did this.

Lets move on to the problem of dating and identifying.

First , if you serious in this endevour then I commend to you an old chinese ?? proverb which says

                                KNOWLEDGE IS POWER.

Buy The encyclopedia of British Pottery and Porcelain marks by Geoffrey Godden. It never dates so you may find one on ... Ebay or abebooks or a new one on Amazon. My dog eared copy is all of 20 years and I sleep with it under my pillow..

But back to dating ....of the pottery variety that is.

If you see a sign on the bottom of a piece of china which looks like a loosely tied knot, sometimes with initials in it - it come from Staffordshire because that is the county insignia. No other English county would dare copy it. But that does not mean that if the knotted bit of rope is not there it is not Staffordshire many Staffordshire pottery companies do not and did not use it

If the bottom says " Made in England"...  well it was  - but AFTER 1902 so a description which says the piece is Victorian needs.... changing

If the sign on the bottom includes the word ENGLAND then it was made.. in England - but AFTER 1891 and BEFORE 1902. and Bingo ! you have the two golden rules on dating... English china.

If the maker's name on the bottom includes the reference - "Limited" then it's after 1861 though many potters did not use it until 1880. A Trade Mark sign means the piece was after 1875

If you see a series of numbers, normal six preceded by Rd then it is after 1884 . These number were pattern numbers.

The real gem of a mark is an impressed or printed diamond shape with a series of letters and numbers in the corners. These again were signified a registered pattern mark - like a patent  - and they date from as early as 1845 and were used until 1879. From this mark you could identify the very day the poiece wa smade... Fascinating "!! It does NOT mean that was always the date the piece was made- though it might have been -  it means that was the date the pattern was registered

There remains the piece (s) with no name and no marks. There were hundeds of pottery companies in Staffordshire, and elswhere in the UK , some lasted for ever,  some a few months. Forty years of hanging around china and I still, regularly  find pieces with no mark so one looks at shape, design, patterns and colours and somehow experience starts to sugest a possible age. Fine porcelain was often catalogued and there  are sources of information which can help and do readily.  

TRANSFERWARE.  It was made, often using child labour earning a pittance. Children as young as eight summers were employed for their dexterous fingers to apply the transfers around the dishes and plates and up the sides of vases before they were fired in the kilns. Examine any piece and you can look for the joins, like hanging wallpaper only considerably more difficult. 

FLOW BLUE CHINA. One of Staffordshire's happy accidents when glaze was applied to wet paint and the paint ran all over the plates while being fired. Well,  we can't afford to throw it away so let's send it to the Americans they will buy it.  And they did and wrote back asking for more ... We Love they said. So it was refined and today we all appreciate - Flow Blue.  But if the blue does not diffuse and sometime "pool" under the glaze then I challenge that it should NOT be called flow blue.

English China v Continental China. A good general rule if there is no makers mark to tell you,  is look at the white colour. Continental china is what is called hard paste and the white is a thinner, colder white. English china is soft paste and you will find the white colour thicker, softer and warmer.

For those of you with a very fine eye and good light, a  tip about glazing. Glazed pottery before 1823 has a distinguishable .. "ripple" effect to it. They did not know how to apply it without it looking like it was cast on the seas. But in 1823 they solved that problem.  So if you have that old unmarked piece of pottery has that ripple effect to the glaze then maybe you have a nice piece ... 180 years old....