Nail Psoriasis Alernative Treatment

Hi all. I have had nail psoriasis for nearly 17 years now. I am very fortunate to be of a small percentage where my psoriasis only presents in my fingernails. However, my nails always look horrendous, as I right only 4 of my fingernails are ok and the rest are practically cut back to the cuticle to avoid injuring myself. I have tried topical steroids but these absolutely nothing (i think because they cant penetrate to the area affected. I have never tried any of the stronger medication like Methotrexate because I am worried about additional side affects. About 10 years ago my nail psoriasis started to affect my joints in my fingers too by way of psoriatic arthritis. I went to see a dermatologist who gave me a steroid injection in the top joint in my index finger. Not only did this fix the arthritis but my nail recovered and for about 5 years the nail never had any signs of psoriasis, it's only really coming back now but even now it is much milder than any of the other fingers and usually only affects the tip. I have therefore always wondered that if I got all the joints done then maybe it would fix it. My question for the group is about Intralesional Methotrexate, I have come accross this treatment which involves injecting Methotrexate directly into the nail matrix. I spoke to a local NHS dermatologist who said they wouldn't do it. Does anyone have any suggestions how I could get a doctor to perform this treatment in the UK?