ILR SET (O) No reply for 11 weeks, how long?

Hi All.

I went to premium service to Liverpool HO along with my wife to switch from Tier 1 General to ILR on the 5 year basis.
as my wife is been here just for a year, so I was supposed to fill in a PBS form for her ( yes couldn't find out about this beforehand). the HO staff kindly gave me the PBS form which I filled in right then in 20 minutes as very simple form.

but as they had already spent 1.5/2 hours on my application, they withheld the application saying they needed to perform further checks and refused to tell any timescale.

Now its going to be 11 weeks tomorrow, and I have not heard anything back yet. quiet a few things now depending on this and now has started to affect my health, does anyone know what is the usual time period for such cases? and if I can contact somewhere to find out about the progress on my case?

Kind Regards and thanks in advance
Naveed

This may take 6 months. They must have given you a letter and that letter must have some information about ways to contact them