What’s a power up? Is that another name for a pull/chin up?
If so, there are outdoor gyms in a few parks around Glasgow. The Bellahouston Park one definitely has a pull up bar. A quick Google suggests Kelvingrove, Alexandra and Elder parks have outdoor gyms too.
Or use a tree. Or use a climbing frame or swings in a kids playground.
Of course the downside is that all the time spent hanging there, straining but failing, and the painful realisation that you are now too old to do any pull ups, is all done in public.