Tricky to answer as the workload in terms of days on duty varies with how long the duty days are. The following is very general and comes from my old rosters.
If you were at a northern base where the all of the work was Canaries,Greece and Turkey, then you'd work about 10-12 days a month. 10 days off, plus some standbys/leave.
If you have quite a few Spain/Italy plus a few longer flights and you work at a base in the south of the Uk you could work about 14 days. Don't forget a night flight is spread over 2 days effectively.
Leave is quite generous and goes up to 50 days after a few years service. We also have a bookable day off system, so you have some control over some of your natural days off.
Nothing is perfect and you'll never always be able to get all of the dates you want, particularly weekends.
In the summer it is difficult to get an entire Fri-Sun free of duty, sometimes you get lucky, sometimes you can book a GDO, I have done 2 summers where I worked almost every weekend. Winter is easier. You do need to understand and work the leave/gdo system to control your lifestyle. This is more of a problem at small bases.
We have a good lifestyle union agreement which overlays the EASA FTL.
Nothing is perfect, but it works pretty well. Sadly the old charter days of doing nothing in the winter are long gone.