Carl, Too much
Re: UK fuel prices, have a look here for an airfield avgas price league table:
http://forums.flyer.co.uk/viewtopic.php?f=33&t=51535
Remember, these prices are GB Pounds per litre
1 US Gal = 3.79 Litres, 1 GBP currently = 1.52 USD
Hence, using those conversions....
a UK price of £1.60/Ltr = $8.64/US Gal
p.s. lots of grass strips in the UK tends to slightly favour the tail dragger decision. I know it did me.