When he was living in my niece's back garden, he bullied her cats and, after the death of one of niece's cats (who we believe kept Dave at bay) he really tried to dominate the other two.
And when she came down one morning and Banshee and Louie were outside all forlorn and Dave was inside keeping them out, Dave had to go. So I adopted him.
So my guess is that he is a 'one cat in house only ' cat and he would either run away or make a kittens life a misery if I got another one.
I really would like another but I don't want to upset Dave (I do tend to over compensate for him being an ex stray

What would you do? Risk getting a kitten or leave things as they are? It would have to be a kitten because he'd go berserk if it was an older cat.