Hi Rog welcome to AO.
'Veloce's' are very well respected dealer and will know all about the Cam belts, they will also know full well that they ought to be done at 36K, I would be suprised if they say otherwise.
The official position from the ARUK dealers is that they should be given a visual inspection at 36000 miles. Now all mechanics will tell you it is impossible to judge the condition of a Cambelt by looking at it, so in reality this is a ruse by ARUK, what they are doing is simply building some of the cost of replacing the belt into the 36K service. Sometimes if you are lucky the dealer will look at the belt and say, 'sucking on teeth sound' that looks like it might fail, better claim it on the warrenty, that way the lucky owner gets a free belt change.
Veloce's are not an approved AR dealer, so don't have that option also the 2001 car will be out of warrenty so Veloce's understandably won't want to do it. If you do want the 147, and I'm sure you do because it will be a very nice Car, you need to work very hard at getting a belt change as part of the deal, it should only cost them a reletively small amount in parts and a few hours labour, it would cost you a lot more to have it done elsewhere and a hell of a lot more if it snapped a month after you bought it!.
Just a thought about 147's with 17" wheels on, from my limited experiance the ride is considerably worse than with the 16" wheels and the handling not much improved by them, personally I would stick to 16" on a 147, or 156 for that matter.
I think in your position I would scan the Autotrader and see if you can find a similar Car, which has had a belt change and perhaps 16" wheels, try driving both of them and judge from there which you prefer.
Another possiblity is to try a 156, you will probably get more for your Money as the values have taken a bigger hit. Just to compare I reckon my recently sold 2003 156 2.0JTS Veloce 2, would be about that price perhaps a few hundred more, Cam belts and Wheel issues still apply to 156's though.
Good luck and happy hunting