A few concerns;
1). The claim a UK Toll Free number but it is a mobile number - could be that this was coded in the x-cart setup and they didnt change it.
2). No details about where they are located or an address to cross reference the company to the web registration to the physical location.
The following are on the plus side;
1). The web address is registered to someone in the UK.
2). The prices are within the bracket of being reasonable i.e. not a PS3 for $300 from china.
if you think that you want to trade with them then I would ask the following questions;
1). Are they a company, if so ask for their Company Registration Number.
2). Are they VAT registered, if so ask for VAT number.
3). Get an address for them so that you can check that against what is registered at companines house/HMRC etc.
The usual rules apply -- check them out and if you think they are legit then proceed.