So I bought the tickets :-)
I'm flying Friday 10 (December), and I'll be back in Portugal by Monday 13 (December, also).
Looks like I'm gonna be in town for the London Perl Workshop :-) Hurrah! :-D
Everything seems OK, apart from one minor detail... On Monday, my flight is at 8:15 am ;-( Ouch... I don't even want to think about it... :-(