spouse visa mandatory checks

I was an overstayer in the uk.I applied for COA and got married to my british citizen wife.I travelled back to Nigeria to apply for my spoiuse visa and applied on the 1st of april.I latter contacted the british embassy andi was told that they are expecting the result on some mandatory checks they are conducting on me from the home office and this was on the 15th of april.they then sent a reminder on the 21st of april to home office.
i called the BHC again this friday and was told they are yet to receive the result of the mandatory checks from the home office and that they sent a follow up again on the 24th of may.
does anyone have an idea how long this checks take?the wait is really killing me.