Error of law hearing - waiting time scotland

Can anyone advise me of current waiting time for error of law hearing?
History of case:
I am a British citizen my husband applied for entry clearance in August 2015 which was refused on the ground of his bad immigration history we meet all the other requirements.
We appealed in November 2015 eventually case got heard at the Ftt in Glasgow on 31st July 2017 we won this appeal but the HO appealed against the Ftt decision their permission to appeal was then granted on 11th September .
We are currently waiting for date of next hearing does anyone one have any recent experience of this situation

On what basis did they reject... can you let me know if you don't mind. Hopefully it gets sorted for you

do you mean reason for objection to original entry clearance application ?

What is "of his bad immigration history"??

He entered the U.K. Illegally in 2009 before returning home in 2015 he then applied for entry clearance which was refused but we won the appeal at first tier but now the HO have appealed on an error of law ?