I personally would also think in the long term as well, would you and you son ant some later date like to go off and do your own thing. If you want to think that way I would go for two one-man tents. I thought that way with my son, I bought one-man units, I carried on but he as a 31-year-old is now no longer interested. Never mind, I now have tent choices and if he wants to he can always start to hike sometime in the future, his tent will still be in our garage.
Thank for the input & opinions on all of this everyone.
That makes sense. My boy is 14, lives with his mum (& my elder daughter) but I see them very regular (well, not with Covid but under normal circumstances!) so 2 separate tents wouldn't be an issue. What I need to do is find out how the other half
really feels about wild camping because there's no way she would sleep in a tent on her own.