Biasi 24s water leak - DIY repair?

[31satara]

1998 Biasi 24s 47 970 06
I've noticed that the above boiler is dripping water from the diverter valve. It seems to be where the hydraulic actuator goes into the diverter valve body, or where this bit (with the two screws that hold the actuator) goes into the diverter valve body. Can't quite tell, and don't want to disturb anything yet. The leaking water is dark brown in colour and has left a brown/black deposit (getting thicker) as it's dripped/evaporated away. The pressure also gradually drops, I've topped it up again today to see how quickly it falls (probably not really relevent).
Does anyone know if this is a common problem with these boilers? And more importantly can it be fixed? By me? (I'm fairly practical but not an engineer. I replaced the actuator membrane 3+ years ago. That took me a while to solve as I didn't have access to internet help then!)
If anyone could give me an idea of which parts I'm likely to need, proceedure etc I'd be grateful. If it's beyond me, how much should I be paying to get it sorted?

 

[ChrisR]

Looks like a few pounds worth, right?

Sit quietly befoe opening:
http://img132.imageshack.us/img132/7732/28710266sr0.gif

Try googling

 

[31satara]

Hi ChrisR. Thanks for that, now I think I know what I'm looking for. With your photo I can see how it fits better. It looks like the leak may be coming past the o ring on the part furthest right in the photo.
Biasi list the parts at £45.18 - I don't mind paying that if I can fix it! Does anyone know if these bits are easy to replace - or is there a risk of disturbing more of the valve parts causing further problems?
I notice the whole diverter valve is £110. If that's much easier to fit, and less likely to result in further problems I might be tempted to go for that. Any opinions?