im too scare to try this, so i ask first here, what happen if i switch RTH and the vps off? are the drone fly to home point at my setting altitude?

Yes it will still return to home.  It just won't be a precision landing since its not using the vps.  

i recently did a night flight ie no ambient light and therefore VPS not opperational.

Sorry.. RTH function brought the mavic home perfectly but on landing i had to be careful as it came down very fast. I realised that due to no VPS the drone did not seem to be able to detect the ground and seemed as though it would land at high speed unless i controlled it

There is a descent speed limit, you will have no problems.

hallmark007 Posted at 2017-7-30 09:56
There is a descent speed limit, you will have no problems.

my descent speed could have been related to sport mode i may have been flying in at that time - i should have/could have switched sport off but did not think of it at the time - in fact only thought of it now as a possible reason since u say there is a descent speed limit.
will do another night flight and try recreate the situation and work out why the rapid descent occurred - will also test a full RTH in the dark.

Bekaru Tree Posted at 2017-7-30 11:02
my descent speed could have been related to sport mode i may have been flying in at that time - i should have/could have switched sport off but did not think of it at the time - in fact only thought of it now as a possible reason since u say there is a descent speed limit.
will do another night flight and try recreate the situation and work out why the rapid descent occurred - will also test a full RTH in the dark.

3 M/S for Mavic

Andry, do not worry, disabled VPS will not affect the normal RTH. Please take care when you landing.