well, my first impression is that they seem legit. they have listed phone numbers and an address. why not contact them and ask if they can arrange an appointment for u to inspect the stock..
also, their website:
http://www.star-jam.co.uk/ only seems to have just one page..no info about how to pay etc. Scam sites always try and show lucrative prices and always say how they take payment.. they seem like traditional scammers who do their business offline...
so in all..i'd say, call them up, give them a visit, see how they operate. they seem legit to me so far but you never know the length some scammers might go to