Suggestions for a compact system cam?

[Basalt]

I want to get a compact system cam for running time lapses - main reason being it'll save the shutter on my nikon from a lot of wear and tear.
Sensor size doesn't have to be huge as it'll be used mainly to render HD video.

Key things:
macro - I was thinking of one of the micro four thirds cameras adding extension tubes as I won't need auto focus.

External shutter control is essential

external power a big bonus so I can leave it running for weeks.

Full manual mode - definitely needed.

And of course price - I want something second hand and under the £300 mark

That still leaves a wide selection of cameras, any recommendations or 'Do not touches'?

 

[Terenas1986]

On snapsort you can browse around in cams. I did too.