Hello Charlie,
Just one other point, which may not be relevant but could be vital.
A pop top will increase the height of the vehicle.
Obvious, I know.
But if Plymouth is like Torbay, or other coastal towns, that increase in height may just prevent you from entering any car parks with height restriction barriers.
Without a pop top, I have less than 5 cms, and that is assuming the barrier is at the height stated and is level !
I have a huge beach side car park near me, and many campers cannot enter it ! Everywhere else ? Double yellows !
I would agree with other members, think twice. However easy is it to climb up, as you get older .......
Consider a tent, or an awning.
Awnings are not easy to get for Alphies, but many members have fabricated their own roofattachment rails.
Search for awnings, there's lots to read !