The M&K speakers are so cheap in the US that it makes sense to fly over there for a week holiday, buy them on the spot, supervise shipping and still save on what it cost to buy them over here.
Consider
this offer for pair of new S-150THX for £621 vs. the UK price of £1700.
Add shipment costs, VAT, customs, plane ticket add there is still money left.
If buying a whole 5.1 system, you can buy at least two extra pair of speakers to compensate for the luck of warranty cover (5 S-150THX speakers are £1,553 + costs in the US vs. £4,250 over here). So if any of the speakers develop a fault, just traw them away and use the spare.
Most dealers would not ship them directly, but if you phone them and explain that you are coming personally to buy from them and ask for assistance to organise courier service they'll help.
Same applies to subwoofer, although they will be more costly to ship due to larger weight and size. Consider MX-350 model, US price £742 + costs (
here) vs. UK price £2,095.
This surprises even me: PHENOMENAL.
"I spoke to a lady there who was very helpful ..."
Whith this kind of mark up she has every reason !