I've just bought this invisible shield as it's supposed to be quite good.
Its' $24.95 + $3.49 shipping to UK. BUT you get 20% off using this code IPHONEINCA (this code will expire soon!)
Plus another 20% from quidco. so about 40% off - which is MUCH cheaper than buying from the UK. I chose the $4.50 delivery option as it's only about 70p more and gets to the UK quicker.
Quidco has just tracked at £3.37 and paypal receipt shows £17.72 so it cost me £14.35 delivered to the UK! Cheapest possible price, even cheaper than here in the UK!