Just a heads-up for anyone buying a GK MB/MBP cab from USA - which I did a few weeks ago as I was unable to source one (MBP115-11) from any UK outlets.
My cab arrived within a week (well done FedEx) but was 115Vac type; I emailed the relevant fella at Sam Ash, Miami & he just said that I should buy a converter (step-down transformer)..!
I wanted some sort of refund - he offered $25......I refused & we had a few more exchanges.
Then, I decided to open up the amp section of the cab (I'm a qualified electronics engineer btw) to check for a voltage selector & on the PSU/amp board was a jumper enabling either 115 or 230Vac....! I moved the jumper to 230Vac position & all is good - cab works fine on UK voltage supply.
I hope this info will be of some use to someone finding themselves in a similar situation :-)