Having seen this serial twice on VHS I opted not to listen to the existing episodes, merely 1 and 4 only. It's a pity they're missing as they're actually very good. From the shock tactics of the IE guards with the lorry driver to the Doctor's reaction to computers and Jamie and Packers banter in part 1, plus the helicopter escape in part 4, they sound very good.
As for the serial as a whole, both times I watched it I found it overly long and grew tired by the end, though I guess this can be chalked up to the scripting issues in season six and how this was originally going to be just six episodes (if it had it might've been considerably better). So a good story, just long.
The Crusade next.