Even if it is an approved design you still need to make sure that the individual aircraft will gain a permit in the UK if imported. There have been cases of aircraft on the Experimental category being imported and refused a permit or having to make expensive alterations because they do not comply with UK specifications, e.g max weight is too high or the C of G is outside acceptable limits. Remember that each aircraft is an individual construction and only as good as its builder. The rules are, I believe, much more relaxed with experimental aircraft than they are for Permit aircraft in the UK.