Do you mean the order book. If so I am not sure that anyone offers that level of data (level II) historically only the live orderbook.
I know even the subscription providers sharescope and prorealtime that I have used would struggle to provide that kind of information.
Maybe you would have to go to the professional LSE LIFFE for that kind of service/info which would not be cheap if available.
As another issue I noticed you are trading Prospreads - what is their charge for trading the FTSE Indices. Are you happy with them?
Which are you trading 3m etc. and what style are you using to trade day - tick charts or swing.
Cheers Shaun