I'd like to say Good Luck and hope it goes better than my interview did with XC trains for the RSM role based at a station in the SW.
The day started with just 4 candidates, as there were 2 no shows. As we arrived we were signed in and sat in the mess room. Offered a drink. We were sat in with other XC staff. They were friendly enough, but at interview stage its slightly uncomfortable. We were shown into a training room within the building where we sat and had a very brief chat about the job by the XC customer service manager. The recruitment woman then added a little, which included "No one leaves Bristol, and we don't have any positions for RSM, but the management have decided that we can have one more based at Bristol." This chat lasted in total about 3 minutes. We were allowed to ask questions, but to be honest the job isn't rocket science. Then we sat 2 tests. They are similar to the practice test papers your wife has/will be sent. Basic Maths, plus timings, then English comprehension exercises.
We were then given the group interview. This was an excise where you have 10 minutes to decide what equipment you would take in a plane crash. You do this on your own. After 10 minutes, they come back into the room, with a few other XC peeps, and you then discuss what items you would take with you.
Then you are sent on a break. Now, because the ice had been broken, we chatted among ourselves. After 20 minutes we were called back to the training room. Now if you are successful at this point, you then do an individual interview. Unfortunately, we were all dismissed as unsuitable, with added fluffy terms such as XC high standards. In hindsight, I wish I had asked a few questions at this point, regarding this rather shambolic interview.
Either the position was filled internally, or from another recruitment day already, or HR was just going though the motions to please the management.
I'm certainly not a bad looser and understand that I may not be suitable for some jobs. However, I worked for BR in the 80's as restaurant car staff on Intercity trains from Euston and St Pancras/Nottingham and have spent the last 27 years as airline crew, and been with the UK major airline for over 14 years. I'd have taken the maybe unsuitable line, but the fluffy and flannel with high standards blah takes the biscuit. She did start going vague and loosing track here LOL
You can ask for feedback, which 2 weeks later has not managed to be sent.
My tip to your wife is get her to chat to the other candidates before starting the interview so to break the ice,(say who you are, what you do work wise .. as cabin crew the group discussion would have flowed beautifully if the other candidates had know what I did

) as XC interviews you don't introduce yourself to the other people once the interview has started. It would make the group discussion flow much better. Also get her to explain that to others being interviewed, so they don't just stare in amazement at her LOL
Good Luck and wish your wife all the best