What Zarek said. A lot of these places have lots of exclusions and clauses in place to avoid paying for pre-existing conditions. The insurance I get from work (for example) had a very distinct one about not paying for any long-term conditions and associated health issues that arose in the 2 years prior to falling under its umbrella. Your only hope (without lying to an insurer, which would be some form of fraud I assume) is the NHS, if you want it cheap/free.