I've extensively questioned SAQ. The rep is a bit contradictory in places.
SAQ Q & A's
The unlimited package is £58 a month.
They'd call 400gb a month excessive. They don't traffic shape or port block as a company policy.
Off peak is 12am-6am for BUSINESS usage. Residential has no off peak.
If you can only get upto 8mb presently, you won't be getting the 832k up-speed either.