My thoughts, it's an 8yr old car that is not complex and needing specialist servicing. I would use an indi all day long and put the saving towards your road tax.
Resale? I can't in all honesty imagine a buyer giving you any more. Once a motor is out of warranty, most folk use non franchise. As long as the car has had a service as per schedule with evidence, then that's good enough.
FWIW I've bought cars with full dealer history, only to discover they've not changed service items they've charged their customers for. EMG Ford in Haverhill one owner Focus. Service receipt charged for the pollen filter, but it'd never been changed. The big manufacturer sign above the door counts for nothing IMHO.