Should always start on the button, things to check in this order:
Check fuel pump primes when u turn the key
Remove ECU plug and clean up the connections (I would disconnect the battery before doing this)
Replace blue temp sender - deals with cold starting & running
Check battery & starter wires, clean up all earth connections and replace any wiring that looks old/tired/very rusty
Replace dizzy cap, rotor arm & plugs. Leads too if you can stretch to it!
Should do the trick
