Have you checked the starter motor it self. Ive heard that when the clutch flywheel starts to break down the fileings end up clogging starter motor. hence making starter not turn properly
Hi, and many thanks for your input. The thing is I get no clunk sound as if it's trying to engage the bendix also there is no battery drain (lights dim) when I turn the key. However to follow through on your thoughts of it being the starter motor, I connected a cable to the starter motor positive and put a meter across that and ground whilst someone tried to start the car. and found there was no supply getting to the starter. So I still suspect it's a relay/contactor problem intermittently failing to pull in, also when I had my old battery in and it went flat, the dials used to spin right round and back again, also my computer settings would be reset to default. That does not happen now, the new battery has enough full power to take the cranking current repeatedly if needed.
However, thank you so much for your reply, every suggestion is much appreciated and worth investigating
My very best regards,