I slept out in my garden again last night.
When I've used my tarp my 'difficulties,' for want of a better word are at the point when I want to get properly dressed/undressed in order to get in my bivvy for the night and to overcome similar problems when I get up.
Assuming that it's not raining, my routine is to lay out my main groundsheet, with mattress, bivvy, and sleeping quilt on top, and then erect my tarp around it all. I then start to organise myself and I like to have something dry to stand on as I do it. The small square sit-on mats for me are just too small so I now have this 2' x 3' wide piece of groundsheet alongside which I use because I can stand or sit on it depending on what I plan or have to do. I haven't done anything yet about how to do it when it raining, I'll get to that over the next few days. Oddly, in all the nights I've used my bivvy from 2019 I have never yet had to face a night of rain.
In addition, I've found out that the thin Odlo baselayer that I recently bought is very comfortable and I can easily double up and use it as a top for sleeping in. To complete my night attire I've just ordered a thin Odlo pair of tights so that my skin is not directly on the bivvy material when I lie down for the night. That is the one problem with my Hunka bivvy, the mattress has to be under it, not inside. I've tried this and the internal space left is just not enough for me. If I was to buy a Hunka all over again I'd definitely purchase the Large version.
As I've discovered bivvy camping presents its own little issues and problems to resolve, getting in and out of a bivvy into the open air is not the same as being able to perform these functions from inside a tent.
I spent last night outside in my garden again trying to perfect my technique. I can also now erect my bivvy in the dark which means that on a real walk all I have to do is find the spot where I plan to sleep, then go to the pub. Then when I leave, wander back to my chosen spot, organise myself in the dark, then get in my bivvy and go to sleep.