sounds exactly like our ds!
he's now 8.5mo, and we've had some improvements lately, as he's started to eat more food. He can now go to sleep without being fed to sleep (I feed, put him in cot, and he rolls around a bit, maybe whines a little, but not proper crying, then drops off). did this accidentally - the first time he'd had a really late afternoon nap (5-5.30, with a bedtime of 6.30), and I fed him till really full, but he wasn't overtired, so he lay in his cot quietly and then fell asleep. This didn't happen before 7mo, and we haven't been able to replicate it reliably until 8mo. The late afternoon nap is key for us though.
He still naps only on breast/in buggy/in car, but we've progressed to
- napping in buggy being rocked but not walked
- napping in buggy just stood still (but still outside)
- napping in buggy outside front door but still (get some strange looks from postman!)
we're now working on napping in a still buggy inside house.
Not sure how much this helps, except to say that things can improve, and I understand how hard it is, really. I keep reminding myself it can't last forever - he'll be sleeping all day and night by the time he's 15!