Clothing Conversion Chart

How do I work out the size of some clothes etc. to sell on eBay?
I am in England and want to know what is the best chart to use to establish what size garments and shoes are that I want to sell on ebay. Unfortunately the size labels on some of my families items are missing or they are foreign & I cant find good all round conversion chart on the internet. Any tips please.
click european sizing and it shud come up with no.10 being ebays own, hope this helps
[Prototype] “Filthy Clothes” TEXMOD w/ ENB [HD] – GTX 260