Do you really think BA would deliberately hire less experienced pilots?
FLR, whether it is deliberately or otherwise, the fact of the matter is that the BA assessments will always contain an innate bias towards those who are closer to their academic years (in terms of number of years since secondary, college, and university level education).
The verbal reasoning tests written by SHL are used by many top blue chips to hire GRADUATES. They measure skills that one has supposedly just learnt by attending Uni. They are a method of measuring skill when one does not possess the experience. In the same way that you cannot expect a rookie to have the kind of knowledge you would expect from experienced staff, you cannot expect someone who is 25 years post his college/uni years to perform well at paper based tests that bear no resemblance to the job or the lessons life has taught them.
Let's not even discuss the silly and pointless 1980s computer games that we have to play.
My opinion is that if you fit the mould you get in.
The "mould", as defined by the assessment process is therefore something which goes against ones maturity (age) and homes in on ones inexperience.
BA, EZY, FR wouldn't dare publish figures on the average age of new pilot hires (not that they have to), as it would expose their not so very blatant ageism by design.