No starter on key turn

New fault l322 td6 2003
Sometimes when I start car it does nothing
I insert key
Turn ignition on
Turn to start but no sound

In park and neutral same issue
Lock and unlock same issue
To rule immobaliser out I have powered trigger wire on starter
It starts straight away
Then it starts on key for a while
Maybe 1 hour rest it wont start again

Where can I find starter relay
Should i look here or at ignition switch

Have a check that the battery terminals are clean and tight and also have a look at the engine earth strap passenger side down by the engine mount they corrode for the fun of it.