However, if you sign the "transfer to 100% Mortgage" (which aparantly you are already according to Brendan) then you will be liable for the LPT (Local Property Tax) on the % owned by the council (which they don't really own). Might as well throw out the English language at this stage.
As a matter of fact, All 50/50 shared ownership people here paid roughly 90eur. Since I'm annuity (100%) I paid 180..... you can do the math...
That's why they want you all to transfer to 100%, but be weary of those bearing gifts. The council are either paying this LPT and need to make this adjustment to get shared ownership into the LPT net. If you see no reason to switch then don't, if you do your LPT will increase, that is guaranteed.