Why not use one of the reputable suppliers?
Such as Hyperdrug/Canine Chemist...
Have you checked Companies House to see if they are a registered company?
Just checked for you, no such company registered at Companies House
http://wck2.companieshouse.gov.uk/aa7b3278035d81e2956d15f3de6369b1/wcframe?name=accessCompanyInfoThey don't display their company registration number nor their VAT registration number on their website.
So you can't really do many checks on them.
If you use google maps the postcode just shows a house in the middle of the countryside.
They don't display their pharmacy number either, unlike Hyperdrug.
Would hope that you don't have to register with your credit card details...if you have I'd be tempted to cancel
the card as it may be comprimised.
I'd say suspect...and say pay more for your prescriptions needed at bone fide pet pharmacy.
As per some news reports yesterday re 'fake' sites if it seems to good to be true...it often is.