I've got GAS for a new amp head - my GK MB500 has been great over the past few years but I'm yearning for a change.  I've sold a number of unused pedals to fund this new desire of mine.   I have a budget of approximately £850-900, pretty generous given I'm your classic weekend warrior. I'd been pretty set on a Markbass head but, over the past few days I thought I'd see what else is out there and boy there is a lot right now!!   Unfortunately not many places have a broad range of heads in