My bus has been stood over winter & took it for a run yesterday but unresponsive power - any ideas?

Did you service and tune it first?

Take out plugs, clean and gap them. Adjust valves, do compression check. Put plugs back. Clean/check points, adjust gap and timing, lube cam and points hinge. Clean carburettor - evaporated petrol might have left white gunk in jets. Adjust and lube. Clean oil cleaner. Change oil, clean strainer. Check/clean fuel pump strainer. You might have to flush and refill fuel tank if it's had 6-month old petrol sitting in it.

Start up and try again. Run some fuel system cleaner (Nulon etc) through it.

Don't forget to service the brakes - and change the brake fluid.

Thanks Phil74Camper.
I've booked it in for a service & yes you're right about the brakes they are poor too! Many thanks & I hope to not leave it sitting so long next time.

No worries. Today's fuels seems to leave a gunky whitish residue if left to sit in the carb bowl for months - it may need to be taken apart and scraped / blown clean. I had that problem with mine last winter when it was off the road for a few months.

yep it really screws up ya mower