Cycling alone or at least 2m from anyone else seems to be perfectly ok. It's just groups and cafe stops that are to be avoided.
Gyms and pools are open with the same advice to keep distance.
https://www.bbc.co.uk/news/uk-51933762
If you are under 70 with no underlying conditions you can still be active outside as long as you stay at least two metres (three paces) away from other people. So walking the dog (or even your neighbour's dog), going for a run or going for a bike ride are all fine - provided you keep your distance.
Public spaces such as swimming pools and gyms are not banned - but if you use them, be sure their equipment and surfaces have been thoroughly cleaned. And of course you can do your bit cleaning any equipment you use. Dr Foster says it's preferable to exercise outside.
Team sports are not advised for now - but tennis is ok for the moment as long as you wash your hands first, don't shake hands afterwards and keep your distance.
If you are over 70 and self-isolating, pregnant or have an underlying health condition, but feel well, you can also go outside with the same caveat of keeping your distance from others.
Skippy has a F-you attitude, I'm not going to change anything, keep going to pubs etc.
A thought, if he stopped boozing for a bit, perhaps he could afford a decent new bike