Hi Geoff,
Welcome to T2W,
For info' on the FTSE 100 and its constituents, you can't really do better than this:
London Stock Exchange
If you want fundamental data on constituent stocks - there are various sites offering free info - here's one:
Morningstar
All U.K. brokers will offer charts of the main indices and, in the case of the FTSE 100, all the constituent companies. There are various free end-of-day providers to choose from, this one being one of the most popular:
ProRealTime
Tim.