Thanks guys
Simon - that makes a lot of sense. I'm thinking a humbucker might sound better too as the sound in the bridge pickup is quite thin. I had a cheap hotrail style pickup in an old squier tele that I quite liked, I might try that anyway.
I haven't tried it in the amp, the speakers can be switched separately to the effects, but I'd imagine you are right, it should not be an issue with the amp disengaged. I'll try it and let you know.