Charging the battery and some time overnight the n/s indicator came on and is still showing amber on all three units (front back and side).

Will not work correctly as an indicator, nor when used as hazards. O/s indicator working perfectly.

Disconnected battery and reconnected with no difference and also a short drive proved unhelpful.

Is the problem in the BCM (which I have seen suggested somewhere) and if so can it easily be replaced ?

I don't need the keys reprogrammed as I never use the fob to lock/unlock.

What is a "Ford Model: cooke"  ? 🤔

Assuming the car you're talking about is the MK2 Ka...

If one side of indicators are stuck on it sounds more like it could just be a stuck relay if there are relays on the ka for indicators? I've just done a bit of searching and I can't find anything about it though so it could be that it is something integrated in the BCM I'm not entirely sure. If you were to get your BCM replaced you would need to send it off to have it cloned onto a new or virgin BCM as it is not plug and play unfortunately.

Hopefully it's just a relay, good luck!

2005 model would be a MK1. If you wanted to try a basic replacement pattern Indicator relay, it would cost around £15. Just for peace of mind I would also check the bulbs were all good and well seated in their holders.

Or a bad earth

Thanks guys for your wise words, I'll let you know what transpires....

Incidentally the model is an '05 Streetcar !

I would go for a poor earth. Start by checking all bulbs are secure and holders are clean.

All the bulbs are functioning correctly in that they all work and the o/s works normally, it's just the n/s that is 'stuck' on all the time.

If the relay was indeed faulty would it not either work properly, or not at all ?

4 hours ago, antiestablishmentarianism said:

it's just the n/s that is 'stuck' on all the time.

Fault is with the GEM, most likely water ingress. They are solid state (no mechanical relays).

That's just 'cos I'm not very good at formfilling, especially online !

Recharged the battery but OFF the car and once charged and re connected the indicators behaved normally - hooray !

Could the problem have been that I was charging the battery while it was still connected to the car I wonder ?

5 minutes ago, antiestablishmentarianism said:

Could the problem have been that I was charging the battery while it was still connected to the car I wonder ?

No... Probably would have 'fixed' itself if you'd just disconnected the battery for 20 minutes and let all the modules do a simple reboot.