Yorkshire Dales are nice if you pick a good route, great views too. North York Moors next door are a good call if you want properly brutal climbs where you breathe a sigh of relief at a mere 20% gradient. Lake district is a little busy on the roads for my liking, even on the back lanes, but I dare say wouldn’t bother many.
North Pennines offers lots of good climbing (winking sheep as mentioned, hell of hexham, etc) and some brutal exposure to the weather on the wrong day.
Northumberland offers a vast playground of rolling hills, more gentle than most of the above. (And there are more interesting routes than the cyclone) Same with the Scottish borders, which harbours some of the longest and quietest roads imaginable. Though road surfaces vary wildly.