Danzet,
Firstly, a big Welcome to Bmed!!
I think you will find it pretty difficult to move to Spain. May be in the past but not with the regime in place at the moment.You have to be within an hour and thirty minutes from LHR and if your late you will lose your job. In the past crew have tried but have ended up moving back to England due to the stress/cost. One girl was asked to leave in the past due to being constantly late. It's also not very nice for crew to be carrying you on flights because of fatigue. People who commute usually do an extra 4-5 hours per day.
A standby ticket 60 quid plus 35 quid a night at a B+B. If you do that say 3 times a month, 400 quid on work related costs. We don't get paid that well! (average 1300-1500, plus on leave you get 1100)
I think you will find it a logistical nightmare especially in the summer. It is pretty difficult to get on flights at the best of times from Spain, hence, the really long days.
Answer to your Q's, No standby in Office - too busy should be resting before flight, B+B far better but consider the cost. Staff travel 2nd floor all the agents are V. Good.
Finally, I don't want to come across as rude but if you really, really want to live in Spain. Why apply for a UK carrier? There's plenty of airlines there.
Happy Landings