I'd second Helen's recommendation. MyTracks charts are fine if you only want to display a limited number simultaneously (4 max). Their silver service $19.98 (free if you have an account with ODL securities and place at least one deal on-line each month) plus $15 per month for AIQ r/t charts (or $25 for a feed to Sierra charts) plus exchange fees ($32 for r/t LIFFE data).
Total if you want AIQ charts and LIFFE exchange is $66.98 per month, or about £44. So you need to take 4.5 points out of one ftse future contract per month to pay the fees.
Also if you have an account with IB, you can feed the data into Sierra charts ($40 per half year) although you only get live data, so if your connection drops there will be a hole in your chart. But you can also use MyTrack to feed sierra which also fills the gaps for up to 14 days.
IB only £1.70 per side for futures, tight spreads and quick fills.