federico
I'll try to answer some of your queries.
1. What is CAP?
CAP is an amount of work that the company want you to complete in a month in order that you get your basic salary. You achieve CAP by doing a series of trips/flights that each have a value associated with them, known as trip credit. Add your trip credits together and you have your monthly credit. Compare this to the CAP, if you have more trip credit than the monthly CAP, then the excess goes into a 'bank' that will allow you have a slightly easier month later.
When you join the fleet, you will be on a 'Blind' line and CAP is not an issue - so don't worry, by the time you've been in long enough you'll know all about CAP and credit!
2. Why are Gatwick trips good?
Matter of personal choice really, some people live closer to LGW and the commute is easier. Some fly in from destinations only served by LGW. Some prefer the choice of trips -- the Carribean routes are ex-LGW for example.
3. Holidays and work?
In each 6-month period (one runs Apr-Sep and the other Oct-Mar, I think) you get 15 days leave and 7 days Duty Free week - effectively more leave. Associated with the 15 days leave are 6 Wrap Days - don't worry too much. The leave arrangements are pretty good.
On a month of full time working I would anticipate working 17-18 days in a 30-31 day month.
HTH