200tdi starting problem

Hi folks, any brain waves re my '92 200tdi Disco starting. Problem is very intermitent, turn the key and nothing happens! turn the key again, nothing happens, continue for 30 seconds or so, then it starts. I can hear a relay clicking behind drivers side footwell panal, on investigation it is the front window relays clicking.
Always starts first thing in the morning.Problem now beeen going on for 6 months.
Changed starter motor twice
Changed ignition switch (complete assembly)
Possibly the alarm system breaking down?
any ideas?

I'd suggest it might be an earthing problem. Check the battery connections to chassis, chassis to engine, Alternator and Starter cables at each ends .. if any look at all dubious or feel a little loose or look corroded or frayed then replace them.

Hi Paul thanks for suggestion, I thought of that and added another earth strap direct from Battery to engine block. although I will check all other cables again. Sheepdog