There are ways and means of checking out (UK) companies before you give them money. Eg,
www.companieshouse.gov.uk will give you free information on whether companies filed their last accounts properly (a good indicator as to whether they're experiencing financial difficulties) and information on whether their directors have ever been in trouble (try Terry Venables as an example). There are other agencies (perhaps someone else knows contact info?) who can perform further checks for a fee, although it will certainly be a lot less than you stand to lose.
Oh and BTW - don't pay up front!