A lot can be achieved, both physically and mentally, exercising in the open air and sunshine.
Which is helpful as, right now, it is one of the reasons the British government allows for people to leave their homes.
So use it.
By combining simple, effective exercises with an exhilarating warm-up and a sensible timeframe, the park can be your fitness friend. For myself, a quick run followed by simple full-body exercises (examples of which demonstrated here in this video) can deliver real results. Simply choose a tight, regular schedule to exercise (daily, for 20 minutes will do it) and you're good to go.
But the important thing is to remain active, add structure to each day and to embrace the fresh air and sunshine that is available.