My L/H shifter has started to play up and doesn't like drop into the granny ring and when it does it takes 3-4 seconds then releases.
Does anybody know of somewhere online that sells L/H shifters in XT M780 10spd rapid-fire, non I-spec, rather than in pairs?

I can only find pairs for £50

L/H doesn't matter what speed you rear mech is, so just about any L/H shimano (and SRAM actually) will work. I probs have a spare SLX or something shifter (with 2 way release), non I-spec that I could part with if you start getting desperate. May or may not match your other shifter though.

I thought CRC did individual shifters though...

2 year warranty on XT from CRC

Couldn't be your cable could it? I've got an XT R/H shifter that won't drop onto the very highest gear unless the cable is tip top.

Already replaced the cable and outer.

I'll email CRC as that's where it came from 14 months ago.

Put a wanted ad on STW, there must be loads of spare shifters going for a song now everyone is on 1 X something.....

Good thinking on the wanted ad. In the meantime, I've email CRC to see what their verdict is.

skoosh of wd40?

Skoooooshed it already.

I have one.

Of M780 variety?