Giving the ex-cadets a refresher makes a lot of sense. A few quid spent giving them some time in aeroplanes (or better an MCC type sim) will allow them to hit the ground running when they get to the type rating. I trained a lot of these cadets at FTE and they only got a 20 hour MCC rather than a 40+ hour JOC - so they don't have the same level of training to fall back on as some other did. 5 years was along time ago and standards drift, too - most pilots will pick up many bad habits in 5 years and a little refresher/standardisation training will go a long way.
Think how much it costs for 4 hours remedial training on an A320 full-flight sim during a type rating - taking up valuable time at an expensive TR training centre with a training Captain. Compare that to an extra few days training in an FNPT2 MCC device at an FTO such as OAT or FTE and you can see the savings to be had.
BA tried to give their cadets a few sim rides in the BAC 111 sim when they were kicking their heels in the early 90s after the first punch up with Saddam Hussein. Any brush up before a TR helps - and all credit to an airline that is sensible enough to spend a few Pounds/Euros to save many more.