It is illegal and it's easy for them to give a fixed notice. I think what the article is suggesting in that it's difficult to punish cyclists for more serious offences (which may include them cycling on the pavement).
It's illegal under law, but guidence* from the top is that it's really only illegal if it needs to be, so people causing distress, riding dangerously etc.
It's been this way for over a decade, since the FPNs started.
Basically if you need to ride on the footpath (e.g. safety), do so but be considerate.
Also a
pavement (footpath) here is only next to a road, so part of the carriageway, if it is not next to a road it is not illegal in anyway unless they have a by-law to restrict it. Many snickets, footbridges, parks.. have these by-laws in place, you'll see the good old and ignored signs. Some pedestrianised areas have the by-laws in place too.
If this article is what I think it is, they just want to introduce/update fines and term for death by dangerous cycling.etc. there are already terms used that carry up to 2years.
Basically make cyclist think a bit more about the consequences, which of course is great, need to make drivers do that too.
*I hope the article mentions and links to the guidence police officer should be using.