Hi there Tom, the TBots units are fine (though a 200mm aeriel on your bot is a bit short), I still use one for my wheely bin robot. The problem is likely to be what everybody else is using! Namely Spektrums, once you get a number of them being used they interfere with 40meg units. We had increasing problems with not being able to control Skink (on 40meg at the time) as more people started using Spektrums, in one fight (16 bots)we had no control at all, when it was on its own....perfect!
The only solution was to buy a Spektum (£60 off e-bay), weve had no trouble since.
Not good news for you, sorry!