Interior Design Advice

I’m currently renovating a 1940s/50s house in Dublin – very standard semi-D of the period and want to put in a reasonably period-appropriate bathroom but am having problems sourcing tiles. I’m trying to locate rectangular polished ceramic tiles (100mm x 200mm or close) but literally cannot find any. Any suggestions for suppliers would be appreciated, or indeed any suitable alternatives. I’m trying to avoid the shock of walking from a very ordinary 1950s house into a minimalist, hotel-chic marble bathroom but I do want something reasonably lux.

Any advice would be appreciated and btw this is quite an interesting forum! Enjoyed the threads on pastiche and the PVC window debate!