Don't you know a plumber, that could come and remove the rads for you? Then put them back on when you're done? Obviously you'd have to add that to your price... In all fairness to the plumber, it's not really his problem. If the customer won't wear the expense, you'll just have to slot them. If you go down that route, don't re-use the bit you cut out, cut new pieces, and get them tight. It'll be less noticeable.