I know that lots of people want to out-cynical each other on here, but... my take on it is to wonder whether the ROSCOs would be happy with this story doing the rounds to "panic" people into tying their trains down into long(er) term leases.
We are in a situation where the ROSCOs have had a relatively lazy time of it for a generation without having to worry about much competition (relative market share between the three of them seems little changed, to my untrained eye), most responsibility for refurbishing/ upgrading stock falls to the TOCs to pay for - despite the ROSCOs knowing that the January 2020 deadline is approaching for accessibility they've been pretty reluctant to plan ahead and stump up to upgrade their own trains.
ROSCOs acting a bit like slum landlords - sweating the assets, expectant the tenants to pay for maintenance (rather than the landlord upgrading things out of their own profits). Not a great advert for capitalism. But why break sweat, why compete with the other two ROSCOs and bring prices down, since you'll all suffer. TOCs can't bring in foreign stock (because it'd be too wide for our infrastructure) - what are they going to do?
In the last couple of years, we are finally seeing competition, new entrants to the market (Hitatchi, Vivarail...) and the monopoly broken up - ROSCOs can no longer rely on the same income from their two hundred 142/143/144/153s (due to accessibility changes) - they need to shape up (which can be hard to do once you've got used to lazily banking the cheques each month without doing a lot of work).
If the Irish are sniffing around the second hand market (they can obviously bring in "narrower" UK trains, just as UK locomotives have moved overseas) then I can see the ROSCOs being keen to promote the story to try to encourage The Powers That Be to put these trains on longer leases in the UK instead.
If they really want UK trains then I'd rather we dumped the 175/180s on them - non-standard trains that are no better than what we have (and not particularly reliable), but I can see it looking politically embarrassing for TfN etc if services in Northern England continue to suffer from overcrowding whilst "our" 185s are moving abroad - that'd make for some nice cheap headlines - so can we use the "interest" of the Irish to rattle a few cages and try to get trains with guaranteed leases here (like a football agent trying to use newspaper gossip about another club to secure his player a juicy long term contract at their current team).
Certainly does the ROSCO no harm for us to be discussing this anyhow!