said that he had to stop an Easy Jet off at FL140 when he was passing FL134 (already cleared to FL150) , due to late climb of the aircraft ahead by Swanick.
A couple of minor points.
Why was an a/c cleared to a level still occupied by another? In
anticipation of the a/c ahead vacating the level perhaps? Ask yourself if this is a wise technique.
How do you know the previous a/c wasn't mainting FL150
for a reason?
How do you know that the previous a/c was actually in communication with the next unit? Perhaps the "late climb" was because there was a comms failure of sorts? Perhaps there were other reasons the a/c was not climbing? A technical problem for instance. There could be any number of reasons, couldn't there, beyond "late climb... by Swanick" (sic) who might have had very valid reasons for not climbing the a/c, reasons that you might not always be aware of.
What I'm getting at is, assumptions can be a bad thing... be careful.
Rgds BEX