To answer your other question, an MRI scan can cost about €400, but it depends on where you have it done.
Also, if the centre that the GP is referring you to isn't a Category 1 centre with VHI (i.e. direct payment, you don't have to pay a cent), ask the GP or consultant to send you to one that is. There shouldn't be a need to visit him/her again, you should be able to arrange a new referral over the telephone.