if theres moisture/damp in the cellar what can be done about it , and how much am i expecting to pay ?

If you want to completely get rid of the problem then it will need "tanking".
This consists of using a Bitumen type prouct that is applied to the wall like a plaster coating. If done correctly this will completely seal the cellar from the outside elements.

If the problem is literally moisture, then it may just need ventilation, as you are probably aware, any cold area is susceptable to damp/condensation.

Can't help with the cost.

if its bricks what do you think of these?

Waterproof floor and wall membranes (http://www.drywallandfloor.co.uk/membrane_google.htm?gclid=CML2kZyQ-Y4CFQ1aMAodFDmFwA)

but i be fooked if its rocks,

are dehumidifiers worth thinking about?

impossible to quantify without seeing. you need to get specialist advice.

the "right" way is probably to call a local surveyor and explain the problem (ie explain what you can see - they won't expect you to know the cause of the prolem; that's what they're for). ask for a quote for a written report with recommendations. this will also cover you in case you need to make an insurance claim in future (ie if you present the report to a contractor and insist on a suitable warranty for the remedial works, you can prover in future [should your insurers require you to] that you have in the past undertaken suitable maintenance under the guidance of a chartered surveyor).

alternatively, you could try a few different solutions - increasing ventilation for a start, consider tanking, consider heating etc but if you don't get it right first or second time, you could just be chasing any number of variables - in which case, advice from a surveyor would probably be worth paying for.

HTH