The problem with the Focus variants is that the ones currently listed on Motability are ‘stock only’ pre-facelift models, which are getting less and less available as they are sold.
The new face-lifted ones (which have the word ‘Edition’ tagged onto to their trim level) are not yet on the scheme.
The only way to find if a dealer has any stock of the pre-facelifted ones, is to ring around the Ford dealers – I can’t suppose there are that many in NI.
Saying that, Saltmarine Ford in NI currently have some offers on the pre-facelift Focus advertised on their website:
https://www.saltmarine.com/motability-offers/ford-focus/
Obviously they will be subject to availability, but it could be worth a phone call to them.
I don’t think there are any NI dealers on this site unless they operate anonymously!