Great thanks Tim.  I thought I had tried that but will give it a go next time I'm up. Many thanks.

You can switch to the PLOG during flight by tapping the position report at the top of the screen. If you actually have a flight being logged, you should see an extra section at the top detailing your takeoff time and how long you've been flying, etc.

I do normally use the "fly within 25nm" option however this doesn't generate a plog as far as I can tell this no take off time visible.

Have you tried planning a simple "within an area" local route? That will give you access to the PLOG and other instruments will then be helpful as they'll relate to your takeoff/landing airfield.

Is there a way of seeing what your take off time was whilst in flight (if you don't have a route planned).  I guess you can see it on the PLOG if you have a route however most of my flying is taking people up for experience flights and so I rarely have a route in but I do need to know how long I've been airborne and am frequently forgetting my take off time!