And history will repeat itself (Arriva brought Midland, a company based in the West Midlands who's main work was tendered stuff for Transport for the West Midlands, back in 2012 after winning some 5 year TfWM contracts. A year and half ago, they sold the routes and some buses to Diamond, shut the former Midland depot and kept some routes which moved to other depots (ruining the routes remaining with them in the process!!).)
I believe Midland was the company whose vehicles ran around with 'Choice' written on them in an interesting variety of liveries.
If Arriva seriously believe that they can repeat the Midland exercise with Regent they are more out of touch than I (and others) believed.
1. There are no 5-year KCC contracts. KCC are having a 'big conversation' over subsidised bus routes. Consultation meetings are all in the evening and some in pretty out of the way places so only those with cars can get there. I think it is safe to predict that there will be no expansion of subsidised bus routes. Almost all of Regent's routes are subsidised.
2. A quick calculation shows Regent require about 15 buses to run its operation - and, as some routes only operate one or two days a week, they are not exactly overworked. Sunday requirement is 1. Midland was a much bigger operation, I believe (it certainly seemed so when I lived in the area).
3. Midland took advantage of the opportunities to tender for routes outside of the West Midlands. Regent are too far from the border to tender for anything outside of Kent.
4. There is no-one to sell the routes to when Arriva are bored with them.
5. There is no history of competition between operators in East Kent. The last attempt I can remember was by the now-defunct Eastonways who tried new, different routes in Thanet with some success about twenty years ago. Times have changed.
If this is some sort of revenge exercise after Stagecoach started to operate Canterbury - Faversham - Sittingbourne, then they are ill-advised. I don't think the route is that lucrative and Arriva didn't exactly nurture the Faversham - Sittingbourne section. They will be throwing good money after bad.
I do hope its not true, as then there will be no major independent bus operator in East Kent.
I think you are being rather generous in describing Regent as a major independent operator!