After a lovely 250 mile round trip from Manchester to Grimsby and back via the AONB I have discovered a small puddle on the garage floor under the bike the next day. She has never leaked or dropped any fluid before and from the colour of it I'm a bit worried. [...]From the location of the puddle it's on the left hand side of the bike
That is a common location for a coolant leak. I, too, would be concerned, especially by the color. Since you apparently (??) bought a used bike, I would not trust the condition of ANY of the fluids or filters and check/replace all of it.
I think this time I may have just killed the ignition while she was really hot. Would this cause some sort of overheat as it got hotter after the run in the garage without the fans or am I worrying about nothing.
I think that is worrying about nothing. With the engine off, the coolant will not flow, so the fans being on or off for additional seconds or minute won't really make any difference. If it were hot enough, the coolant will expand into the overflow tank. If the overflow tank, itself, overflows, then your system is over-filled.
I've been looking in the manual and will check the level at the weekend but I don't like the idea of the coolant looking that bad and it can't have any antifreeze in it.
Yep. If I were you, I would automatically just plan to drain the system, flush it once or twice, and fill it back up with a proper mix (typically 50% antifreeze).
Would the water pump be a possible cause of the leak on that side of the bike?
The connections to it, yes. And the connection to the left side of the radiator. And the connections to the overflow tank. You have to pull some fairings, unfortunately, to perform a coolant change (right one for filler, left one for overflow bottle). Make sure to suck out whatever goo might be left in the overflow bottle.
I have looked on fowler's and can't seem to find a price on a water pump. Is it also worth changing the thermostat at the same time?
I have never heard of a Concours water pump failure. Certainly possible, but that seems remote and premature. Same thing with the thermostat. If you were overheating, you would see that on the dash. Mine has never run the temp up beyond one bar from the top- and it has to be REALLY hot outside and a lot of stress on the bike to get up to that temp. If the fluid were low, that could do it. If it overheats while not moving, fan failure can do it.
As a side note- also make sure you are using the correct high-octane gas, especially during hot weather, especially if you push the bike hard.
