I'm very doubtful that you will get an A2 printer for the budget you have. Add another £1000 and you may get something basic.
A2 printers are also very expensive to run and tend to be slow.
How many of the fanzines are you wanting to print? In my company, it is not economical to print anything greater than 500 copies with the inkjet or laser the equipment we have here, whatever the size and format. Even though we have large format printers, because of costs, we would only print ten copies maximum on those. Anything greater than that we farm out to a contract printer.