Thanks A.Y.
Just in case it's of any use to anyone else, here's a quick update:
I found a number of Sony Cybershots such as the DSC-W380 within budget (around the £120 mark for the camera & £150 for the Sony housing), but by this point I'd seen a number of mentions of the Canon G11 and the Panasonic LX3 which both seemed to be considered far superior to other compacts on UW forums.
Both cameras are around £300, but a hasty revision of my total budget to £500 got around that inconvenience and I did a little more research. The Canon S90 also came into the frame at this point- essentially very similar to the G11 but around half it's size. I looked into housings, which quickly ruled out the LX3 due to the fact there's no Panasonic housing, & the 3rd party alternatives smashed my newly revised budget on their own. I had a play with the S90, but it felt too much like; too much like an ultra-compact I suppose- I'm not disputing it's ability, but didn't like the placement of the shutter button which I had trouble finding by feel alone, & overall impression was that it's a little too small and fiddly for me.
So the G11 then. Seemed like there were a reasonable number of housing & lens options as well as a reasonably priced OEM housing, but I'd read that it was pretty large in comparison with the others. Couldn't find one to look at in any of the local shops, so did a little more reading online (just to reassure myself) and became aware of a phrase I'd vaguely noticed before but hadn't really payed much attention to- Micro 4/3rds.
It was around here that the budget packed it's bags and left the building.
I have to admit, I was intrigued: small enough to carry around more-or-less in my pocket, but with near-DSLR quality?
I looked at the Sony NEX-5 w/16mm lens (around £550) and the Lumix GF1 w/20mm lens (around £100 less). I liked how the GF1 looked, and the write-ups of it married with the 20mm lens were pretty glowing. The NEX-5 sits in the hand more comfortably, but I'd read that some of the menus/manual features are more of a hassle to access, particularly underwater. I looked at the Olympus too (EPL-1 I think?), and it felt nicest out of the three to handle, but I was put off by the limited choice of housings.
My rationale now was that for not a lot more cost than the G11 I'd have so much more image quality, and the flexibility to use numerous lenses on top. I'd conveniently forgotten the issue of housing, but when I did investigate I quickly realised the obvious fact that it's not cheap, with all the dome ports, lens gears, etc. Near-DSLR quality; near-DSLR cost I guess.
Then I had a call from my local shop who told me they couldn't get hold of the G11 I was hoping to take a look at, but they'd just had a delivery of the new G12. I dropped in to take a look, and it immediately just felt right. It wasn't as big as I'd imagined, and to be honest I realised the size over the others was a large part of the appeal for me- it felt substantial but compact at the same time.
It's only just been released and the best price I could find it at was £450, but then the G11 is still around the £350 mark, so I figured what the hell! The differences are not massive between the two (G12 has better video capability, second control wheel on front, etc) so I admit it's probably just the thrill of having something which is brand new, but I've placed an order. The canon housing looks fine to me, for starters at least, and is available online for around £160; so total cost is a smidge over £600 which is double my original budget, but gives me a pretty decent compact for land-use now and plenty of room to grow if I go further down the UW route.
Regards
Graham