As I’ve said, what grates everyone seeing the uncommon and unprecedented events that happened with the 442s (which were 40 years old btw) and ÖBB Talents and now automatically assuming any new orders (including this very large one) can just be cancelled like that. It’s so very unlikely.
In the event of 701s being cancelled, SWR would either have to arrange to re-lease 458533/534 or do without, and 458007/017 have already began their longer haul refurbishment at Widnes, ditching the ex 460 car at Long Marston. The thirty 707s are spoken for and cannot return (or remain in the case of the last 12) just because SWR decide to ditch the stock they replaced them with. 456s have began to be scrapped. At least five or six 455s have gone off-lease and would need to be re-leased to come back, and 455740 is as good as a shell.
So SWR would have a severe stock shortage on Metro routes, even with their disgusting timetable cutbacks on many routes, until whatever stock they ordered instead arrived which would take 3 years minimum - and then could have similar acceptance issues. The remaining 455s are NOT acceptable as a permanent fleet so they would have to order a replacement for the 701s, and there’s no way First would overhaul them with the limited time left so the fleet would just continue dying as it is now.