If anyone in the UK has this problem I can recommend BPSC in Eastleigh near Southampton. Barry Phillips has been working with magnetic compasses all his life and now has a small maintenance unit set up in his garden shed with all necessary equipment and spares. Barry very effectively refilled my compass and removed an large air bubble and tested it with vacuum equipment for £30.

BPSC , 16 Penshurst Way, Byatt Wood, Eastleigh SO50 4RJ
Tel 07710 092885