Essentially, one third of the fines never get paid and it's too costly to follow up. Usually it's Germans who are not used to the concept of speed limits and if you are from abroad, then it's difficult to track you down. Still, 60% of fines sent to Germans are paid, whereas only roughly a quarter of those expedited to France are settled.
If you want to see what you might be looking at:
This is the tariff system
Consequences to be faced in your case depend on how well the Swiss and British police work together. There are agreements with certain countries to put pressure on people to pay up their bills.
However, as you massively exceeded the speed limit without being arrested, what may happen is that, should you be in Switzerland and get caught up in a "Verkehrskontrolle", they may see the previous offence and hold you responsible there and then. This has been done in the past, as the archives of the city of Zurich show.
I presume it is superfluous to say that you shouldn't be speeding in the first place and that any consequence to be faced should not be grumbled at.