Octavia not starting intermittent

Octavia 2 2.0 TDi DSG 2005 50,000 miles

All lights come up as usual, OK. Glow plug & air bag arm go out.

Turn key to start cranking and nothing happens, no obvious noises at all.

Try again or later may or may not start, once started OK if restated again.

Taken to Skoda garage no faults on VAG com or faults found

Anybody had similar problem or any ideas?

Anybody know if starter can be shorted to operate when this happens?

There is a 40 amp fuse for the starter, does this supply the starter motor mounted solenoid? Would applying juice to this operate it or is there a CAN bus or other communication with starter motor itself needed? I believe there is a small wire to the starter, does this come off the fuse above?