Seems a bit expensive to start trying to pay for the costs of sourcing/integrating a new type when you've just taken over, especially when you're possibly having to launch a lot of new routes and/or you have a bunch of your current aircraft potentially sitting doing nowt.
Anyway, if these aircraft were for the LHR-ABZ/EDI slots released by the merger I'm not sure how anyone can know now with certainty.
Afaik, the slots have to be allocated through a competative process and are unlikely to be in place till S13, so you surely couldn't be certain at this point that you'd get them. What happens if you start signing up for 170/190s and then don't get he LHR slots?
One thing is for sure - we need some communication soon on the way forward, whether it's trips to HEL or 170/190s!