@FirebirdArts Certainly!
To be honest, water clear resin can apply to any of 3 resins - polyester, polyurethane or epoxy - it's really a property of the resin, rather than a type of resin.
The fact that you specifically asked, and they gave you that answer suggest to me that it may well be polyester resin - it's by far the cheapest resin (£8/l vs £45/l) and far inferior to the other two in terms of strength, so they may not have wanted to admit that that's what they were using. Or they may simply not have understood what you were asking. The only way you'll know if by going back to the maker and asking specifically whether it's polyester, polyurethane or epoxy.
Of course, depending on what the item is, it may, or may not, make a huge difference as to what resin they are using - is it something that is fragile, or will be handled, possibly dropped, or is it something that's fairly solid and just going to sit of a shelf?
Hope that helps, feel free to come back to me if you need any further info.