Hi Yasco
You do not need to be a member of the CSP to work in the UK. However, you may find that job advertisements say 'MCSP preferred' (especially for the NHS). Vist The CSP for details on the benefits of being a Chartered Physiotherapist.
As for the job situation... There aren't many at the moment unfortunately unless you want to be a researcher or university lecturer.
Hope this helped a little.