AC compressor pipes seals

[scooper1000]

Hi I am planning on replacing my AC Compressor as it failed a few months ago and getting things ready cos once you start you have to finish the job, I went to my local Renault Dealers to get new pipe seals the little tiny rubber rings and...I have to buy the complete kit £36 shock horror LOL, I have found a seller on Ebay (china) who does a fair selection 100 rings of different sizes for £7, But with my luck they will not have the correct size.
So does anybody know what the correct size is please or a place where they can be purchased.
thank you in advance

[snapdragon]

Some of them look like hula-hoops (potato snack) rather than normal o-rings. I also need to change the compressor and wonder whether to bother, already replaced £140 of dealer-only pipes 2 years ago due to them leaking at the flanges.

[scooper1000]

Thanks for the reply answers are a bit slow coming these days,,I only work on my car in the drive way so waiting for a couple of nice days has it looks like a bit of a job, having to remove bumper and auxiliary belt..I can only take it off and hope seals are OK...
thanks again