I’m a UK seller, but dable mostly in raw and graded Japanese cards. If any of the cards you’re after is Japanese PM me your wants and I’ll let you know if I have them.
I can recommend MagicMadhouse myself, prices for singles may be inconsistent there sometimes but their international shipping options are very decent. They are very professional.
We definitely need more sellers in the UK
I’m still looking for the UK equivalent of someone like @thecharizardauthorty. I would love to find a decent, reputable source to buy all my stuff from if anything just for the complete peace of mind when buying sealed product etc, Places like MagicMadhouse don’t tend to have many if any old cards/products (WOTC) nor do LGS’s. I have never used Cardmarket yet but i do check it regularly just incase anything pops up but in my experience so far theirs not a lot of old product there either… Again UK sellers are pretty scarce on there too.
I remember around 10 years ago there was a seller on eBay called something along the lines of ‘TheCardSeller’ - had everything WOTC to D&P when they were the latest sets.
3 packs of base set for £20, 10 packs of any EX series for £30… dreamy days.
I remember 4 years ago there was someone UK based selling sealed WOTC products fairly regularly on eBay without reserve, they didn’t seem to be that organised though - putting up 1 listing a week. I forget who it was. Deckki used to be good for graded cards.
I had always planned on selling individual cards on ebay, but never got around to doing it. I mainly have singles for base set, jungle, fossil and then newer expansions from BW, XY and SM.
I know it’s not exactly what you’re looking for but I list parts of my collection that I no longer need on eBay and I’m happy to do deals on here if you’re interested in anything.