Hey i put up thread yeasterday looking for info very similar to your complaint except mine is my ACl.
i have problems standing- which would make sense as its the opposite ligament to your injury.
I've got an Wikipedia reference-linkMRI and the reckon its a grade 1 acl tear with a slight thickening.
I really feel i need an Arthroscopy as the pain i get is like someone throwing a doorstop into it.
We have a similar health system to Britain here in ireland- its called the HSE but its not as good as the NHS.
I've a consulatiion next month and i'm going to beg for a scope as that should find what the proplem is. Apparantly if its only a Partial Tear of a ligament it should only be tender for 5-6 months at then depending on the thickness left your knee shoudl be pretty good. Mine still aches & months later. I feel your pain though- it would drive you crazy!!!!!!!