>>I have a marketing plan which involves contacting UK web designers
>>& hosting companies and getting them to refer work to me
we must get 30 - 40 spams a week asking exactly the same. we get them from russia, india, croatia, czech republic and many other places.
in effect, you'll be asking people to hand over work that they would normally do themselves. there isn't really any benefit to most web designers and web hosts in giving away their income. if they have any surplus work, they'll normally pass it on to someone they know and trust, and in return, they'll get work back another time.
admittedly, very few web designers and web hosts do any real SEO. they may seem like a good target, but if their sites aren't optimised, why not? if they haven't paid anyone else to optimise and promote them, what makes you think they'll pay you? even if they are prepared to pay for SEO, why would they pay you when they could pay as little as $2 an hour for someone in india to do the same?
if you want to go it alone in SEO, my advice would be to build a good track record so you can demonstrate it to others in order to gain work. it could take you several months or more, but if you want any real money from SEO, you'll need the track record.
i walked out of a £42,000 a year job a couple of years ago to do web design / hosting / ecommerce / SEO and so on full time - i had already been doing it all part time for a while. it took me a long time a lot of very hard work to start earning enough to live on, but then i was trying to do a lot of things at once. you may be able to do it in less time than i did just by concentrating on SEO.