Top hose
 

I had to post this boring thread as checking out a possible air con fault was shortening my life. Sorry guys. Anyway, now and again I noticed less p/s effort - mindful of the pump running dry I checked the fluid, all fine. Then, the odd hiss became apparant. Then, luckily, the telltale whiff of coolant replaced the telltale whiff of leaking cambox gasket (so slight not worth the effort of fixing). My top hose, as a result of it's OE wire hoseclip had sprung a pinhole leak, squirting onto the p/s belt, hence the noise. Happy days - all I need is a new hose.
By the way, after a winter of storage and Vol*o use it seems to fly, perhaps by October it'll have gone 'flat' - we'll see!