Updated : Sep 2011
Jamie,
You will pay about £90 + VAT for the medical test if that's arranged by the DVLA. This is classed as a private assessment and you can go to your GP to have it done. Different places will charge different prices and while some medical advisors charge £25, others can go as high as £120. Usually the price includes filling out the application form on your behalf and sending it to DVLA.
The test is supposed to reveal alcohol abuse from High Risk Offenders (HRO) and if the results come back negative, you would be refused your driving licence and might need to wait another 6-12 months before you can apply again.
If you want to know more about the DVLA medical test, please have a look at the article on
drink drive medical test.
Good luck & let me know how it went!