This is mere speculation of where I believe they could be ideal so here goes and like everyone else I’m thinking local to myself.
They’d be good units for Leeds - Nottingham, Leeds - Carlisle and Carlisle - Middlesbrough connect. These could interwork over the course of a week or so for maintenance flexibility. Would give more appropriate units for the services than planned (195’s for Notts and 158’s for the other routes) and could help with a cascade of units. Replace the god awful 155’s with 158’s and cascade other 158’s to routes such as Leeds - Lancaster/Morecambe or Leeds - Southport replacing the wholly inappropriate 150’s from this route. The 195’s released from the Nottingham services could also work more class appropriate commuter routes replacing 150’s.
The 175’s like all early Alstom products had a torrid introduction mainly, I believe, due to lack of maintenance supply support in the early days. However, the 175’s along with the 458, 460 and 334 fleets ended up having much work done on them and were amongst the most reliable units in the country. Sadly the 180’s have chopped and changed operators and remain a real problem, especially the Hull Trains units. If my speculative idea came off (which I doubt it will) the 175’s could be based at Heaton alongside the GC 180’s and this could be beneficial.
All the 175’s need is a thorough refurbishment. The seats are comfortable, the layout is good, the luggage space is more than ample but they have mainly 20 year old trim which needs refreshing. A great unit which needs a future.