I hadn’t heard of an increase in speeding penalties, but then I don’t own a car. It sounds overdue to me, given that I estimate speeds of up to 40 mph on the local 20 mph limit road.
However, before you spend too much time on this, please look at http://product.itoworld.com/map/124?lon=-1.26757&lat=52.38270&zoom=13
You will find that the speed limit coverage is very patchy. Not even all major roads are covered and the coverage of 20 mph limits will be particularly patchy.
I don’t know if any of the paid for mapping databases have better sources for speed limits, but crowd sourcing is not something you should rely on to protect your licence. I would expect even commercial providers to disclaim responsibility for relying on them rather than using your eyes.