that would be a relatively easy restore job, you say it went to England?? is the British proof marks still visible?? then just chemical strip, polish out where any rust has taken place and then get the gun, black oxided, cheapest, simplest, easiest way to go, and NOT that costly.....its the better polish and prep work that makes the refinish prices costly...shop around
and as noted above, a basic 'parkerize' job would be and do , just as well, and that too is much cheaper.......
zinc phosphate if you want gray, and manganese if you want black
