I wanted to start running ages ago but got too impatient doing C25K and instead did my own weird version of it - run for as long as I could, walk a bit, run a bit etc. I started doing parkruns and I've settled into using this style/approach... but it's now been quite a long time. My 5k run time is getting really good (around 30 mins, so good for me!), but I still don't have the stamina to run for any length of time.
Should I continue as I am, and eventually the stamina will come, or should I go back to doing a C25K to build it up? The method is obviously tried and tested, so I don't know why I thought better 
Any advice from the resident run experts?