Thanks both for the suggestions.
Maybe daytime naps together could work, if he falls asleep in bed next to me, that would be one step closer to falling asleep in his bed by himself, I guess! I just worry he might expect to breastfed (as I feed him lying in bed at night) but it's worth a try. Plus snuggling up together in bed is nice 
It's always DH who gives the bottle (for obvious reasons) so I'll suggest the bouncer to him. We discussed it tonight and have decided to use formula for the bottle attempts for now. It's just too upsetting to waste expressed milk, but if he does start taking the bottle again I can start expressing again too.
purple
We did try the dummy again (several days/times in a row) but he still wasn't at all interested! He seems to have worked out how to suck his thumb 😍 So maybe he will start doing that, although he's not doing it much at the moment.
At night he is in the bedside crib on my side of the bed, so I just scoop him out to feed him in bed and then scoop him back again. I do my best to stay awake so I can put him back in his crib, but if he's been waking a lot I do occasionally fall asleep with him on the boob. It's fine but I just have to be vigilant about keeping all the pillows and covers well away from him, and I can sleep better if I know he's safe in his crib.
Funny you should mention the car, it can take him a while to fall asleep when we're driving (and usually a bit of protest crying) but if we time it right he usually sleeps longer in the car than in his crib.
Rocking to sleep is definitely the quickest method (compared to car or pushchair) and takes around 5-10 minutes, but it's pretty back-breaking as he's so heavy!
I've been using a technique I read about for extending his naps beyond 1 sleep cycle... he usually wakes up after about 35 minutes so at that point I watch him like a hawk for signs of stirring, then pick him up and rock him before he wakes up, which helps him to go into another sleep cycle. I've only tried it a few times so far but it seems to be working, touch wood! The idea is that he gets into the habit of a slightly longer nap and should then be able to carry on sleeping himself without me having to pick him up and rock him halfway through. That's the idea anyway!!
Sorry for the long rambly post 