Smooth attempt to shift your argument Leggy and yet you've still failed badly.
It'a almost as if the amount of foreigners playing in England has no noticeable impact on the quality of "English football" whatsoever...
Though through the 60's and 80's (up to Italia '90) England arguably have performed better than they have since the start of the EPL.
The evidence isn't all that compelling though, is it? Especially when you consider the win was in 1966 (where I've started from here).
Before PL:
Win
SF x2
QF x 2
Second round
Group x 3
DNQ x 5
After PL:
SF
QF x 4
Second round x 2
Group
DNQ x 2