DS is 20 months & for the last month has been in a single bed with a rail. For the first week & a half it was smooth sailing but the last few weeks have been very trying as he has sussed that he can get out of bed himself. His bedtime routine is shower then a book & then he gets put to bed. It can take anywhere from 30 mins (on a good night) to an hour & a half (the longest yet) to get him to stay in bed & go to sleep. He gets up constantly, over & over, sometimes within half a minute of having been just put back. It's driving us insane. He's usually fine with naps, it's only with night time sleeps.
We have tried cuddles & softly, softly approaches which haven't worked & are now saying "bed" firmly & just putting him in his bed. He either laughs, cries or gets up again anyway.
We'd love some tips or advice on what other parents have done to overcome this. Before offering advice though, its worth knowing we won't smack & won't shut his door to lock him in (he has toys in his room anyway & I don't want him to associate going to his bed or room as a bad thing) - same with putting up a baby gate. So any ideas that don't involve these are welcome.
Putting him back into a cot isn't an option either.