sending in evidence for esa

Hi
i am currently in esa sg and recently filled in esa50 , when i phoned dwp they said they have sent a letter to my gp on 5th oct I'm assuming this will be the sea 113 form ? i phoned gp the receptionest said it had not been filled in yet so they have had it since 17 days ! can anyone tell me how long the dwp give them to fill it out and return ?
Also i used the excellent guides on here to fill out my form but i didnt have any recent evidence the only evidence i have is a mental health report from jan 2017 which states everything in detail but i used this the last time i applied is it possible to use it again or will they still have it on their system from last time ? any help will be greatly appreciated.

AJ

I can't see anything on the form on the accompanying documentation that specifies when the form needs to be completed by but I assume that Maximus will be expecting a quick return and I would assume within three weeks.

We have seen them progress the claim without the form being returned in good time so you might want to jolly your GP surgery along to get the form completed.

Gordon