Depends what you have been doing in the public sector. If you're reading newspaper, going for long lunch breaks and surfing internet all day then obviously don't expect yourself to be very useful in the private sector. If you're doing real work then the private sector will gladly welcome you. I know a few who have switched out and they have successfully continued their progression up to the top in the private sector.

One's potential and success is not limited by where you work and those who work hard are able to achieve success wherever they are. If you're stuck, sometimes you have to look at whether you are the problem, instead of blaming the organisation.

i work in a very slow paced sme.

stagnating.

however, i'm getting cold feet at joining public/civil service - bureaucratic way of life.
would there be lots of reporting?
endless presentations?

Depends on the culture of the organisation, and the working style of your immediate supervisor. But in general, there are quite a fair bit of writing and presentations to be done. In fact, the only way to distinguish yourself (for good career development) is to be good at writing and presentation.

If you're worried about these fundamentals, would suggest for you not to join.