Recommendations for sites to purchase Seresto collar?

[Diddleysquat]

I have three prescriptions for Seresto Collars for my dogs but I have no idea where to buy! My vet doesn't sell them and didn't give me any clues.
I'm nervous of spending money on this sort of thing on the internet as I'm aware there could be all sorts of fakes (they are not cheep!).
Anyone got any recommended sites to shop on?
Thank you!

vetuk.co.uk

viovet.co.uk

petdrugstoreonline.co.uk

animeddirect.co.uk

Thank you! Have you purchased from these people?

Personally I have bought from Vetuk and Viovet

The rescue I am involved with uses the other two.

Vetuk may be a bit more expensive sometimes but it does seem to vary but excellent on deliveries and communication so I prefer them

Interestingly, I ordered from vetuk and didn't need a prescription. Could have saved myself £40 .