Evening Phil, I'm in Mossley Hill so will happily pop by to give you a bit of advice if needed though the guys on here know what they're talking about! Deffo listen to Lithofin Bob, Lithofin products are generally spot on. I've used the cleaners and sealers for years. The only other impregnating sealer I would recommend is Dry Treat tho this is considerably dearer. As for grout, as previously mentioned, Tilemaster is superb. Biggest issue I can see there is getting the old gear out. Original geometric floors were often butted together so removing grout without damaging the tiles is a pig! To be honest and imo if you get the cleaning process right the grout is most often restored to a good level.