It's impossible to say with any certainty. The longest time between 2nd stage letter and approval I've seen is 1040 days, and the shortest is 1 day.
The best I can say is that 50% of applications get to approval within 110 days of 2nd stage letter. 71% within 150 days, and 91% within 250 days. This is based on 136 applications recorded on this forum.
Also, don't hold your breath in July - it is usually a very quiet month for approvals.