The Mastiff was taking longer to spin over before starting from cold and would need choke for longer than it used to before it would idle properly-time for a carb clean!
I was hoping be able to remove the float bowl in-situ (which i couldn`t) and wasn`t keen on removing the carbs unless i really had to!
I got a large can of Carburetor Cleaner from Toolstation For less than three quid.
I removed the float bowl drain screw, drained the petrol and gave a good squirt of Carb cleaner down the drain screw hole, replaced the screw.
I removed the petrol supply pipe from the carb and again gave a good blast down the metal tube, replaced the petrol pipe.
I flushed out the float bowl by fully removing the drain screw and switching on the petrol tap.
This all took about ten minutes, and resulted in instant starting, a choke that could be knocked off far sooner, and a better bottom end response-RESULT!!