Hi @james6belgravia , and welcome to GADC.
Nice little drone collection you have going on there! 
If you haven’t already, take a look at the Map of Members. This is a relatively new feature so not everyone is on there as yet, but I’m sure there are other members in your neck of the woods that will come and say Hi that may also have ideas on locations.
(Don’t forget to add yourself to that map : Members’ Location Map - A Guide)
I’m “local”, up the road in Eastleigh … and I was down on Southsea on Tuesday … flying out, and around, Spitbank Fort.
Also, if you’ve not seen it, check out our map of places where members have flown. Obviously, this is mainly populated by posts from the more sedate drones than yours, but there’s always a change that it might be of assistance.