10 weeks minimum, blame solicitors for it, they never speak to each other or other companies such as search companies.
They just send letters and wait for responses often within 28 day windows. I'm sure it could be much faster, you have to keep pestering everyone, estate agents, solicitors daily.
It is also best to be in contact directly with the buyers/sellers then you can update your own solictors with the progress.
DO NOT rely on what estate agents tell you, many of them are lying arse holes.