I work for the police as a civilian and I am going through the same process as you.
The OH doctor will probably want to see you and take a history. He/she will then call for reports from your GP and consultant. The on-line referral you mention only refers to the method your HR section will use to contact the OH department. Your case will be referred to an independent doctor who will assess whether you qualify for the upper or lower tier of pension award. The two tiers are as follows:
Be permanently incapable of efficiently carrying out the duties of your employment because of illness or injury - Tier 1 (lower tier) pension
Be permanently incapable of engaging in regular employment of like duration to your current duties because of the illness or injury - Tier 2 (upper tier) pension
The independent doctor will normally wish to interview you before recommending the award to your HR department. They will then arrange with you a leaving date and, more importantly, your pension provision. You should receive a very decent lump sum as you have worked 26 years for the council and your pension will start as soon as you retire.
In my case, I have very recently seen the independent doctor and she told me at the interview that she will be recommending the higher award. I am 61 and have PPMS. I would be very surprised if you do not receive the same award. I am currently off sick as well.
I appreciate your concerns about the process as I felt the same, initially, about the police HR. However your HR department should be able to handle the procedure efficiently, even though it may take some weeks to reach the final settlement.
I am glad you are an union member as it can provide very useful support and you can always ask a representative to attend meetings with you. I did for all my meetings with HR during the initial stages of my application.
Best of luck. I am always ready to help, if within my power.