A referral to an NHS physio should be your first port of call, Shazza. Many of them are very interested and very knowledgeable about sports injuries. You can also get biomechanical assessments and orthotics via the NHS in most areas, but where I work the waiting time for the initial consultation is over 6 months.
Some major orthopaedic units have sports physicians, but again there's a long wait for an appointment and it's a bit of a waste of time if you already know more or less what's wrong with you and what caused it and just want treatment.
A good osteopath will assess you thoroughly, give you treatment and advice, and be honest about how many sessions you need rather than keeping dragging you back with little benefit. Expect to pay £30-40 per half-hour consultation, but if you only need four ou five sessions it's worth every penny.
Cheers, V-rap.