call Brian at https://www.classicvictoriantiling.co.uk/
On the website under the photo of the bathroom with the white sink is the restoration Barry Gregory did on our path. We have been delighted with it and it follows the original pattern which also runs along our hallway. They are based in Muswell Hill.
What kind of mosaic is it? I do know a London-based, Italian-trained mosaicist. On their website, they have big jobs they did with a studio, but they are also doing restorations as a sole trader.
Here's their Insta: https://www.instagram.com/southlondon_mosaic/
Hope it helps,
Some years ago we used George from Victorian Tiling Services. 07944 624 373, email@example.com I don't know if he's still in business, but worth pursuing. Satisfactory service for a reasonable price. He also resealed the floor.