As LikeClockwork says... Halfords is not a bike shop. Halfords is a shop that sells bikes. Boardman are starting to realise this and are not letting their elite range anywhere near Halfords - they've finally worked out that entrusting a three grand carbon fibre bike to a 17-year-old with a hammer and an adjustable wrench is not such a good idea!
However, I don't say this to say "I told you so", Danone - a good LBS will be able to sort out your wheel. It's unlikely to have been too badly damaged if it was just built up badly, a complete un-tension and re-true should sort it out. However, bear in mind that not all rim inconsistencies or wobbles are visible to the naked eye when looking at the rim alone. You can lay the rim down on something flat and get a good idea of how laterally true it is (how much it's bent from side to side) but unless it's significantly wonky it's hard to check whether it's radially true (not round). That said, if it was a completely new rim, there should have been nothing wrong with it...