I realise that the amount of slack was a little excessive, but I am used to bikes that are either:
Shaft drive
or
Off road/supermoto with loads of suspension movement and hence run with more slack on the chain.
However I think the point I was making is that if the chain can go for 15000 miles with only one (admittedly late) adjustment, then how long will it last. I think 25k could even be a conservative estimate.
All this bearing in mind:
MZ baghira 660 - rear chain life approx 8-10k miles (great fun with sticky tyres such as Avon Pro Extreme Rain's, but then again 800 miles on a rear tyre
Aprilia 660 Pegaso Strada - rear chain life 8-10k miles. Great little commuter bike.
Aprillia Dorsoduro 750 - rear chain like 22k miles Fun all the way to falling of when tempting a wheelie
Honda CRF 250X - rear chain life approx 2k miles, mostly green laneing
Keith C