The last post is also including the per diems of 70 Euros a day.
I would say an average month would range from 15-18 days a month.
If stand by at home, one is not paid per diems for that.
All the above is true and forgot to mention that, that is the in hand after tax figure.
It works out at about £38000 taxed at the lower rate of tax (its just below the 40% threshold) + €70 per diem which is tax free. As southcoast says 15-18 days per month is average so you can do the maths.
There is an option to volunteer for extra days over the busy months Jun, Jul and Sep. Do two days per month and its about an extra £700 per month after tax.