The position as I see it is this:
The word "cannabis" spooks the authorities.
It appears to benefit some patients.
At this present time, the evidence for it's use seems a little ambiguous. No evidence of effect, but, at the same time, no evidence of no effect. Stuff is emerging from the FDA I believe.
It would appear that you can purchase sub therapeutic doses on the high street.
The MHRA have pounced on this, and have made it a "medicine" with all the restrictions that brings.
The MHRA have realised that some people appear to benefit, so have recently rescinded a little.
I think, the bottom line is, at this point, we need more evidence.