Cheapskate company-formers?

We don't get to form many limited companies - about 1 a year and for purposes of controlling the process, we've done them ourselves for a while.

However, there now seems to a breed of uber-efficient company-forming services out there, who are happy to form a company with you providing online info, for the vast cost of £25 + VAT. Since this is all electronic, CH will only want £15, but a tenner for forming a limited company seems a bit stupidly cheap. I presume they make extra money from passing on services to the new company and passing new company details on to those junk-mailers who like that sort of thing.

It just leaves me feeling, 'where's the catch?' and scratching my head at their business model. Has anyone used these kinds of companies (this one's www.uk-plc.net) and experienced any problems?
Marion Morrison