Originally Posted by N9MD

Possibly a naive question --- but are you sure you did not call the UK and get a rate quoted in Pounds (GPS = Great Britain Pounds Sterling)? That would reflect the apparent conversion rate from USD to GBP giving you the 370 quote.

It's been my experience that the quote is based on your home residence --- so booking AVIS via a European or US agency while using a US home or business address gets you US prices. (I could be wrong; but, if so, don't tell my wife.)