Hey, make sure to add maxspeed:type tags when adding/updating maxspeed tags. A list of maxspeed:type tags is available on the wiki here: https://wiki.openstreetmap.org/wiki/Key:maxspeed:type#United_Kingdom.
Also please don't split ways at junctions to add speed limits like this: https://www.openstreetmap.org/way/1373475907. It's best practice not to add such small segments when the speed limit is different on the main road. Cheers.