On Fri, 27 Nov 2009 16:39:29 +0000, Dave Plowman (News) wrote:
Suppose they could be repositioned - but not until I'm certain they can't
be removed.

You might be able to drill them and replace... failing that:

1) Completely drill the entire area and weld in new metal with appropriate
hole (pain in the backside, but perhaps appropriate if restoring something
"properly")

2) Move the fixing points as mentioned (cheap and cheerful, hopefully
do-able in such a way that someone in the future could still do point one
above if they wanted)

cheers

Jules