Well I tried it last night ( first time since I wanged it)
I warmed it up all good, after 30 mins of playing the volume dropped a little and it had a high pitch noise?
I switched it off changed the socket it was plugged into and noticed it wasn't biased right... So did that as well. My instinct was telling me it might have been the fan making the noise (as the grill with the fan flew out when dropped)....... Gave it a bang,3 hours playing afterwards and no problems at all :-)