OK well somethings still not right. Since I refitted the breather hoses correctly. I've been using the bike to commute to work on ( A short trip 4 - 5 miles max ) and I've taken it on one shortish ( 20 mile ride ) and all seemed well. No more oil in the exhaust starting and running well.

I rode it to e.d.'s last night 60 miles or so everything fine, no trouble with the bike, just a small touch of carb icing but nothing serious.

Tried to start the bike this morning to ride home and same symptoms, bike wont start, oil in sight glass when I checked it was black again ( it had fresh oil when I changed it last ) and the wet tarmac underneath the bike had a rainbow oil slick on it.

I havent ridden the bike and left it at Liz's and I used Liz's bike to get to work this morning. Viney thinks the likely culprit might be a blocked breather hose. If anybody else has anything useful I would appreciate it. Otherwise its going to the mechanic to get looked at properly. I havent taken it apart as it was to dark to do so, but I suspect the airbox has oil in it again.