In the u.k, how much does it cost to achieve a blood interview next to a private g.p?

I am convinced my thyroid is underactive(from past experience) but my nhs g.p say there is nought wrong. I am so tired all the time and can narrowly function. A friend told me i will get a better service next to a private doctor than with a nhs doctor.In the u.k, how much does it cost to achieve a blood interview next to a private g.p?
It make sense to get a second opinion-All the clinics below will theory test you for various problems related to fatigue,etc,the cause not well recognised by GPs adjectives the time.
You will not need a referal write down from your GP for breakspear medical clinic-but you will for drmyhills clinic.
The prices will vary from clinic to clinic.
Be easier to see a different GP within your practice. Demand a blood test. Only difference between GP and private doctor is you can hold what test you approaching done if you are a hypochondriac who is willing to settle.
Recently had a blood trial taken by nurse in Superdrug and have immediate result. I consider some other Chemists also offer this type of facility. I be charged around lb8.00 for that particular audition. Perhaps if you telephone round you will find a local chemist to you and bring back a price. Good luck!