You are not paid until you start indoc in Lisbon after having succesfully completed the full training to the company's satisfaction (around 16-17 months after your training starts).
The net figure is roughly equivalent to 40-42k GBP for UK Residents - however, that does include all of the per-diems and it is HIGHLY likely that you will need to spend some of that money. Per Diem (per day) payments are made to you tax-free to cover all reasonably expenses incured while on duty (i.e. dinner, drinks, laundry etc). The company will pay for bed & breakfast (usually 4 star or better) and will also provide crew meals but you should expect to spend at least some of the 70 euros/day they give you.
Also - the above figure includes 20,000 euros per year tax-free which you will probably be needing to repay the loan you will probably need to take out to finance the 70-75k for the course and the relevent food & accomodation.
Hope that helps.
Phil.