transair or sporty's are the ones that i would fully recommend, never had a problem ordering from Sporty's, there is a cost there of international shipping plus $14 but you can find stuff cheaper there than here in the UK.
a set of Bose A20 with Bluetooth and twin plugs will cost £915 on transair but sporty's will cost $1095+14+shipping (guess the shipping at $100) comes to a total of $1209 (estimate) convert that to UK pound comes to £747.40 (estimate)
I would email sporty's and find out the cost.
At the very least it gives you alternative place to shop.
Fats