I think the #GreenParty should spin its proposed #SpeedLimit policy slightly differently - and just say "we will reassess all speed limits on #UK #roads, selecting maximums of 50 to 60 mph where appropriate" this enables use of existing road signs and limits that drivers are familiar with, isn't wildly different from what local Councils and #NationalHighways / #TrafficScotland / #TransportForWales are doing anyway, gives #gammons a less obvious headline than unusual 55 mph limit and they don't have that long attention spans..
Incidentally I've now been driving 7 years and even in that relatively short time I've seen multiple rural roads across #Suffolk and #Essex change limits from 60 mph to 40-50 mph - all areas with Conservative Councils!