That domain name was registered through Identity Protection Ltd. While firms such as that provide a valuable service for, say, hobbyists who don't want their personal details to be traced via their website about their hobby, it can look incredibly suspicious when a trader seeks to hide their identity.
However at least there's a postal address on the website (which is a legal requirement for UK web traders), so that's one test that it passes. However I would expect any reasonably large firm (as that website tries to suggest you're dealing with) to:
(a) trade as a limited company (it doesn't) ; and
(b) to provide a landline phone number (there's not one).
Further, I'm surprised to find that a 'veterinary laboratory' with an 'experienced and dedicated team of parasitologists and analysts' appears to be operating from someone's home on a modern housing estate! (Isn't Google Street View wonderful?)
The fact that payment has to be made through Paypal (rather than directly by using a debit or credit card) also suggests that it's actually a one-man business but the acceptance of cheques (which at least suggests that there's a bank account in the name of the firm) might possibly offer some level of reassurance.