Decided to take the plunge today and replace my top mounts and bearings.

..but the very top nut is baffling me, I loosened it on the car, once the shock was out I clamped the old top mount in the vice and removed the nut completely..

However, when rebuilding the nuts gone on ok but just doesn't seem to do up that tight before the shock itself starts spinning.

The allen key at the top of the shock is clearly there to stop this happening but how on earth are you supposed to get a socket/spanner on and the allen key in at the same time?

Nothing I've got would fit including swan neck ring spanners.. is there a special tool for this job that I'm not aware of?

Grind 2 flats on the socket then put an adjustable spanner on these and an allen key through the middle

or just grab hold of the socket with mole grips whilst stopping the shock from moving with the allen key

ok so Im getting the impression this is one of those improvise situations!! i'm not sure I'd be convinced it would be tight enough turning a socket with mole grips..

..there surely has to be a tool for this?

It needs something like a spark plug socket as they often have cutouts so you can turn them with a spanner.

I use a cordless electric impact driver - does it up in seconds

Have you got the full weight of the car on the suspension? Once it's sitting on the full weight it can tighten up ok.

As Jimbo says, but one of mine still slipped. I "bought" a halfords vortex set and with that you can get an allen key in to stip the shock moving. Fiat use a special tool as per the Workshop manual.

Molegrips on a socket may well work well too

Yup, the vortex kit is very handy addition to a tool kit, I'm armed with one too

I stopped it spinning with a 10mm Allen key wedged in the gap between the nut and top mount. It could be considered the ghetto way of doing it but it's what I came up at the time when mine were spinning.

I got them tightened in the end, the mole grip socket approach worked a treat :-)

They had a few more turns to go as well which has made a noticeable difference.

Problem is I think I'm going to need to repeat the process and strip it down again as there's still some feedback through the wheel which I think is the actual shocks

The vortex socket set from Halfords isn't too expensive and possibly in the sale on at the moment, well worth buying if you do quite a bit of work on the car.