There’s many many many artists in London that probably specialise in Japanese style work, the most famous one is Nikole Lowe off the TV series London Ink. She has her own studio down there now called Good Times. You should look her up. There’s several other artists that are working in the studio too and I wouldn’t be surprised if her knowledge of the genre is rubbing off on them. There’s also ‘The Family Business’ and I think that ‘Into You’ have a studio that area. Hope that’s a bit of help for you 🙂