The strike won't last long if it starts at all, but alas I have an AY flight on 30 Nov at 8 am

I will be flying HEL-LHR-GIG in paid J on BA. The HEL-LHR leg is on AY metal but BA flight number.

What is your experience in cases like this, will BA reroute their J pax automatically on their own flights (there is a BA flight HEL-LHR leaving at roughly the same time) and will I be given priority because of J or onward connections? Who should I conctact a day or two before, supposedly BA?