Time between paying fees and application hand in

[TooL]

I'm currently in the UK just about to transition from T5 to T2(G) (hopefully)
Have my CoS and have just paid my IHS and was about to get the last fee for the application paid up.
But I'm wondering if I do so now but am not planning on having my appointment till Sept 6th, should I wait to pay the application fee or will it be fine with the 2-3 weeks between payment and hand in.
I figure it should be fine but just trying to mitigate possible messes.

Cheers

[CR001]

Are you applying from home country??

How have you completed the 'travel history details' in the form if you are still present in the UK??

[TooL]

I will be handing in paperwork in Canada yes.
I have completed the travel history section already as well. And yes I am still currently in the UK.

[CR001]

What have you put then as your end date for your current stay in the UK?? My understanding is that you cannot put a date in the future.

Date of application is the date you pay the fees online and submit and that is when the window to submit your supporting documents starts counting from.

[TooL]

It never asked my end date in the application.
Yeah I figured that would be the case, as soon as I pay there is a window. Is the length of time for that window known cause I can't find it stated on the site.
Edit: Actually unless you mean the end date for my travel history, which I left blank and it allowed me to do so...