Well heres the second in what will probably be a flood of questions

I don't know when the timing belt was last changed, certainly not in the last 3 years so I'm planning on doing this relatively soon. I will be doing the belt, tensioners and water pump. Is there anything else I should do at the same time? I've seen the auxiliary belt mentioned, is this essential or only if it looks worn? Should the tensioner or guide pulley for the aux belt be done at the same time?

Cheers

I'd replace the Aux belt as well, unless it looks fairly new.
What you want to look out for is the Aux belt tensioner, they don't seem to last too long.
If you look down from the front, and get your eye-line close to the plane of the belt, you can see if the tensioner wheel is cocked at all.

Another thing to check carefully is the Crank pulley, they're another weak-point.

I rate the Contitech cambelt + water pump kit. Nicely made and a reputable name. SAF seem to sell them for a lot less than anywhere else:
http://www.buypartsby.co.uk/details/FIAT/MULTIPLA/1.9/2004/__/54/CT968WP2/timing-belt-kit/

Have a look at their prices for the auxiliary belt kit too. Do at least the tensioner pulley too - they have a tendency to bend off-square and than the belt slips sideways.

And if you want to scare yourself by seeing what an overdue aux belt change looks like, see BD's photos here !

That was my timing belt, not the aux one