Need to check my level as I pulled off the pipe (long story) from the bottom of the reservoir and have a faint noise when steering . Does the green cap unscrew, mine is stupidly tight and don't want to break anything.

Cheers.

use a long screwdriver ,pry it on the gap and turn

Will close my eyes and pray, sorry pry Thanks.

I used a pair of mole grips

I use the key it sits in the groove OK and if you hold the ends it gives some good leverage.