I would suggest working on your FTP (Functional threshhold power). This is the limit of how hard you can ride for an hour. There are set training programs to do this or you can crudely do it by riding really hard for about an hour or doing shorter intervals 20-30minutes at a slightly faster pace. The other one I would consider is riding just below your maximum with the odd 30second sprint thrown in. Not having the easy recovery parts is more related to hill climbing where you stand up round a hairpin or tackle a steep bit.
With that in mind you ride differently up a hill, lower cadence (in my case), standing up etc.
Can you drive anywhere? Roadies always seem to want to ride from the door but mtbers wouldn’t think twice about a drive to a ride. Can’t be many places in the UK more than 60minutes drive from some hills?