I did OLCI for my flight tonight - did it t-48 and got BN2.

Checked again this morning (hoping to see that I've been reassigned to a seat in J) - and to my horror it now shows "Not Available for Online Check-in". The link says that there is an aircraft change, hence OLCI is not available.

I assume this means my BN2 is gone? It's a short (but quite full) flight and I'm hoping for an op-up.

I'm wondering whether I should go down to the check-in counters in Central now and do a physical check-in, to secure a higher BN number? (I work in Central and I'll be using the Airport Express later tonight anyway.)