Intermittent immobiliser fault

[henry the cat]

Two weeks ago, my 2004 Galaxy 2.3 petrol wouldnt start - ignition came on, but it seamed as if the immobiliser was activated as the starter motor didnt turn. I tried again 20 mins later and it started and ran perfectly.

During the last two weeks it has faltered once whilst I was driving. It cut in and out and eventually stopped. I tried a different key which made no difference. After a few minutes I tried agian. It started and has been fine since then (5 days). My local garage ran some diagnostics tests and it came up with code B1612 - which according to Ford technical support means a Key identification error. I read that in early models had similar faults caused by relay 30 getting a dry joint. Is their a relay that would cause it on mine (relay 30 is unused)