I flew to LUX yesterday from T1. Took 5 minutes to get through security. Before that HEL from T3- fasttrack was empty.
As I have said before, T5 is is the worst terminal at Heathrow. Nightmare going in with security and coming back at passport control. Then of course you get the ridiculous shopping centre walk just to get to an overflowing Galleries lounge.
Sadly, I am back at T5 tomorrow - guess I better leave home early.