Is there any restriction on the proximity of water pipework to the
main fuse, meter and consumer unit?

I'm not sure, not having the IEE regs in front of me. I'm sure someone will
come up with the definitive answer.

However, assuming it is allowed, a few precautions might be a good idea
anyway. In particular, avoid using any plumbing joints nearby. Secondly, run
the pipework through a length of drainpipe. This will contain any squirting
or splashing and provide additional mechanical protection to the pipe. Don't
seal the drain top or bottom, you want to see the water pouring out of the
bottom in the extremely unlikely event the internal pipe fails.

Christian.