Going Bo-Bos - Rhyming slang

So an old British expression said to kids around bedtime is "going bobos" for going to sleep, now various sources around the internet seem to offer some strange origins of this expression. I have no firm knowledge or confirmation from any source but believe it to be from Cockney rhyming slang.

Bo Peep is rhyming slang for sleep, so "Bo Bos" derives from that, if you can't get to Bo Bos, try counting some sheep, it might help Little Bo Peep to know how many there are.

Here is Little Bo Peep, followed by her nursery rhyme

Little Bo peep has lost her sheep
And doesn't know where to find them.
Leave them alone and they'll come home,
Bringing their tails behind them.
Little Bo peep fell fast asleep
And dreamt she heard them bleating,
But when she awoke, she found it a joke,
For they were all still fleeting.
Then up she took her little crook
Determined for to find them.
She found them indeed, but it made her heart bleed,
For they left their tails behind them.
It happened one day, as Bo peep did stray
Into a meadow hard by,
There she espied their tails side by side
All hung on a tree to dry.
She heaved a sigh, and wiped her eye,
And over the hillocks went rambling,
And tried what she could,
As a shepherdess should,
To tack again each to its lambkin.