Upvote:1
I returned to Argentina from England; my passport was not stamped on exit there either.
The UK doesn't issue exit stamps
When I took the bus from Brussels to London, I didn't get an exit stamp.
Ah, the laissez-faire French! In all seriousness, in the future always request a stamp if they're trying to break the law (because not stamping you out of laziness is against the law)
Can I enter the Schengen area without a problem, since I didn't get an exit stamp from any of the Schengen states I visited in 2015 before going to London?
Being that you have a UK entry stamp, you should be fine.