lollyone...the central part of the nasal septum is cartilage and if this becomes ulcerated and/or perforated then tis causes collapse of the nose as you have described.
The causes of this are many, but previous nasal surgery is one of the commonest caused, followed by cocaine abuse, intra-nasal steroids (Flixonase etc) and certain other uncommon medical conditions.
You will need to see your GP with a view to an ENT surgeon referral who will investigate your problem.
Yes, you will be able to get this done on the NHS, but I must warn you that the results of septal perforation repairs are not good.
Good luck.