Where next for high speed diesel units?

Electrification and introduction of bi-mode trains is bringing about the withdrawal of many high speed diesel trains in the UK. The nomadic and unreliable Class 180s were withdrawn by Hull trains in favour of Class 802s in 2019, and were transferred to EMR to replace older HSTs, but electrification of the Midland Main Line as far as Corby and the introduction of Class 360 EMUs on the route have once again made the Class 180s surplus to requirements and they have been withdrawn along with EMR's final remaining HSTs. Furthermore, the introduction of bi-mode Class 810 Aurora trains will result in the withdrawal of EMR's Class 222 fleet. The 40+ year-old HSTs were life-expired and due for scrapping, but what of the Class 180s and 222s? Surely these modern trains could find further use? One possible user for the Class 180s is open-access operator Grand Central, which is the only other operator of the type. Where the Class 222s could go is less clear.

Meanwhile on the West Coast Main Line, Avanti Trains is to replace its Class 221 Voyager units with Class 805 and 807 bi-mode trains. In September it was announced that seven Class 221s would be transferred to Cross Country Trains to allow the withdrawal of HSTs.

A surprising announcement towards the end of last year was that Transpennine Express would be withdrawing its four year old fleet of Nova 3 Class 68 locomotives and Mk5 carriages. Their Class 185 DMUs will be fully retained to cover the loss. While the Class 68s could potentially be cascaded to Direct Rail Services for freight use, there isn't much demand for push-pull carriages. Perhaps Scotrail might consider them to replace HSTs on Inter7City services?