OK I've done some research about this on the web and am coming round to the idea. The way it was introduced in this thread really put me off -- I thought someone was selling something -- but I can see now that this is some healthy advice.
I'm not doing this without an aid though because I am a bit hefty and I don't want to damage myself or my toilet. I had a Google round and found this site:
http://lillipad.co.nz/index.htmlHe sells a handmade wooden bench-type thing that is small-ish, elegant, yet suited to the purpose, and he ships from New Zealand around the world. Only, he's not in New Zealand at the moment, he's in Vanuatu (no idea where that is). I emailed him and he said he's got some limited stocks. It would cost £100 airmail to the UK and possibly import duty on top of that; my husband and I are debating whether he should try building one himself according to the instructions on the website. As we have no tools and he hasn't done woodworking in about 25 years, we're not sure about that one.
Anyway, I told the chap I'd pass the info on here. If anyone is interested you are welcome to PM me and I can give you some of the extra details he gave me. I can't say I understand them all but I'm sure you could email him and clarify.
How funny that so much of the world does this but we don't, and we think they're all weird.