Ran through all the guides I could find.

It's level now, well small prints in the centre seem to work great but the adjust screws are right on the limit for bringing the plate down. The extruder nozzles are still touching at the front centre.

I have seen mention of 'shimming' Would this be to raise the extruders a bit I can undo the 2 screws holding them to the moving part and put 2 shims in there between the plate and the extruders. probably raid it .5mm

Would this then give me better control of the print bed ?