I can vouch for Yellow Tim's method of filing and cutting the BB away. After chewing up the grooves on the BB, drilling holes for a bar through, penetrating oil and heating with boiling water all failed, my LBS suggested sending it to a specialist which would have cost about £100. I used a small round file (£12 for set of 3 from hardware shop) and hacksawed to the frame in just one position. Centre-punch and hammer started it collapsing and I could then remove it by hand. Thanks Yellow Tim.