SoloEng,
As far as the 1st question is concerned (re hosting). I'm based in the UK but have been using webhost4life.com. they are pretty reliable (and not too 'heavy' on the load front). all the uk providers that i looked at were far too expensive, webhost4life turns out at roughly £80 for the entire year. i also use amazon S3 for all my file storage, so have been able to use the cheapest storage option on the hosting site too (2GB, of which i use about 20MB, due to offloading all the huge files to S3)
As far as the culture settings are concerned, i changed all my defaults on that page to CultureInfo.CreateSpecificCulture("en-GB"). Haven't got round to testing (or using) that section yet, so can't really answer the question with 100% confidence but i reckon that may well be enough for paypal to be aware of the currency for the site originating the request.
let me know if you discover otherwise.
jimi
http://www.jamestollan.com