This is not tax advice, but as I recall there are certain requirements to meet in order to be classified as a trader ("carrying on a business" iirc), in order to offset losses against other income (these used to be trade frequency, $$ revenue etc iirc)
Otherwise it's capital gains/losses, and any capital losses are carried forward if they can't be offset against other capital gains for the year. Unless you have set up a specific (actual) business, then it's different again. DYOR as I am not an accountant!
