I am not sure I understand, if this was me, giving advice, I would probably tell you what the employers normal stance on sickness is, but not on a condition as that is very individual.
So for instance I would say you understand that you have been off x months be prepared for going to half pay (I don't put it that bluntly but work it into the conversation), this is because one of the things that can knock people for 6 is the automatic letter they can recieve a few weeks before their pay is reduced, which is yet another worry on top of being ill.
could it be that he/she was trying to hint to you that your employer may start capability procedures in the near future if you don't return soon?
Or was the return in 2 weeks on phased return as in you slowly build your hours and this can only last 3 months?
I would if it was me and baring in mind I know nothing of your employer or job, so this is very general, at 7 months of no improvement I would be concerned about the employer starting capability, so I would thinking of trialing a phased return and the 2 week lag from my seeing the person to starting this, is because it gives the client a bit of breathing space to sort out home stuff and try to get back into a more work like routeen, especially after 7 months of not having to get up for instance.
I would recommend, shorter hours building up over a fixed time frame, work from home if available, whether you are covered by the Equality Act that sort of thing.
When working shorter hours it is not unreasonable for your employer to ask you to use you holiday for this if you have a lot outstanding, this is a management issue and OH would not get involved.
Basically, you need to go back to the OH and ask for clarification, if you saw a Doctor their recommended Practice is reading your report to you before you leave and a copy sent to you, but this is not a legal thing, Nurses don't have to do this but most I know do, if you haven't got one, you are intitled to get a copy.
it is a terrible condition, I hope things start to improve soon.