The sightmark Latitude seems pretty good had the pleasure of using one the other day had it next to some of the high end spotters and it was on par.
https://www.opticswarehouse.co.uk/sightmark-latitude-20-60x80-xd-tactical-spotting-scope
https://www.opticswarehouse.co.uk/sightmark-latitude-15-45x60-tactical-spotting-scope
I've used the Lab Radar, Bullet Seeker and the Garmin, from my experience there all great, all work really well.
If you're buying a Chronograph and don't have one, I would get a Garmin. Used it while shooting at Chobham ridges last weekend it captured 98/98 shots fired. Brilliant piece of kit.
I've got a 5-45x56 Highpower with the P4FL, I've been thinking about getting it changed to the LRR-MIL. From reading your post it seems like the only issue is the getting it there and back.
The Arken scopes off Optic warehouse seem pretty solid. I've owned a Riton Conquer X7 3-18x50. It now lives on a 22lr but was really great glass upto around 800m.