I think a good option would be the new Mercedes GLC. You can get it as a hybrid with either a petrol or diesel engine so fuel economy with a diesel should be semi reasonable you'd hope. It's got a claimed range of around 80 miles on electric so should you'd hope pull off 50 miles realistically.
Also of course remember that on longer trips for a reasonable part of it it's part engine, part electric so the fuel economy should also be greatly increased for part of that journey. Only once it's flat is it a regular petrol / diesel with the extra weight impacting fuel economy.
It’s a good suggestion, thanks, but very pricey. Over what I’d like to spend I think. If I was to go the PHEV route I would more likely look seriously at the new Kia Sportage which gets excellent reviews and is better value. Kia seem to be doing a lot of good things with their electric and hybrid vehicles these days, I like the interior layout also. It offers less electric miles than the GLC but enough for daily driving.