Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
Talk with your LDS and ask them where they buy their o rings in bulk. That o ring dealer should be able to match the size (but maybe not the material) of your s95. One problem you may encounter is often there is a minimum order.
Cameras Underwater have the orings Recsea housing for Canon S95
That's a bit harsh ask back scatter or bluewater photo in us or another recsea importer in another country
The price is low so you won't need to pay duty
so are you saying that i should be able to get a "normal" o-ring to fit? i be worried incase it caused a flood though and how can you be sure it is the right size as the recsa ones are different to others ie canon
Exactly, this is what I had to do since Oly no longer makes rings for my 020 housing. You take the ring and housing to the store, have them measure it. They will be looking at three measurements, length, diameter and hardness. If you are very lucky, Recsa used a standard size ring. If not, then most any sized ring can be ordered. I added the note about material since there are three major flavors they come in, nitril, viton, and silicon. When the "correct" size ring comes in, fit it to the housing in the store to see if any adjustments need to be made.
I was also worried about the housing leaking if I used "normal" rings. The solution I came up with was to rig a line close to the depth rating of the housing, find some deep enough water and sink the housing (without the camera of course).
The bright side of the process is that the cost of a set of rings for my housing dropped from $64USD to less than $5USD. The only rings available in my size were nitril instead of the silicon Oly used. Since nitril is much harder than silicon, I store the housing without the rings installed. No big deal since I always break the housing down, clean and inspect each day I dive with it.
This is the company I use (not much help for you in the UK, but it gives you an idea of what you are looking for), Austin Seal Company
If you go this route, you might as well get rings for you tanks, computers and any others you regularly use. As an example, Suunto charges upwards of $20USD for the battery and ring in my computer. The exact same ring, 026, costs me $0.15 each at Austin Seal and the battery runs me $4USD. Suunto is very proud of their battery and ring. That alone has saved me better than $120USD.
Good luck, hope this is helpful and let me know if there is more I can do for you.