I can tell you that for several years I have used the Rosyth and then Newcastle option.
Last year, for a change we came back through the tunnel. The journey from Folkestone to Scotland, even allowing for an overnight in Yorkshire in a very nice pub, was so fucking dismal I'm never doing it again. It was utterly dreadful. Too much traffic and too many shite drivers. My aged pa lives in Sussex so I'm quite used to the journey in a car but always go overnight or at least leave very early to get breakfast at Tebay, but during the day, on a bike, never ever again. Back to Newcastle both ways a couple of weeks ago thankyou very much.
it might cost a bit more but it's worth every centime to maintain any sanity I had to start with.
I'm hoping to try Hull next year but south coast? Never ever.
Oh, and no benefit seeking fuckers trying to crawl into my top box either.