High Risk
As you point out it will cost you a fortune up to 100,000 euro and it is very high risk. At 38 and £50K current salary you will not break even by age 60 (retirement). (Unless you are very lucky) Assuming you got a lucky break - a first officer position at age 40 (they prefer people in their 20s) you would be paid less than half that. You would increase you chances with a type rating though (expensive). You will find some that have been successful although many aren't......