A company in Japan and the UAE who stock lots of Land Cruiser parts at much lower prices than I can typically get them in the UK. There's a thread on them here:
https://www.landcruiserclub.net/community/threads/amayama.144189/
Their website is here
https://www.amayama.com/en/
Bear in mind you need much more than the tank. The tanks are plastic, so you'll want the tank protector (#7760660140) another £160. Straps (#7760160270) to hold the tank in, another £50. Fuel guage sender (#7701035030), another £100. Plus various pipes.
Have a look at a parts diagram on Toyodiy and see what you think. By the time you've got everything, paid thhe courier, VAT and import duty I don't think you'll be much different to Stan's kit.