Put it in context.
£400,000 or so over a 12 year period, and again, a couple with a relatively high joint income. I don't think it necessarily follows that any sort of spend on frivolous or non-essential purchases is immediately going to spark suspicion. As alluded to, my Ex was never off Amazon, constantly ordering homeware from John Lewis, spending a fortune on personal beauty treatments and so on, I never once thought to myself "Oh my, they must be embezzling from their employer".
People seem to think Nicola Sturgeon must have had nothing better to do than sit at home scrutinising receipts for her then husbands spending, which is bizarre because I don't know of a single normal relationship where that's par for the course.
Even with the biggie, the motorhome, people are still questioning why this didn't prompt questions from her. Clearly these questions are being asked in ignorance, because even Murrell, as stupid as he is, didn't think he could simply spend 125k on a motorhome without piquing curiosity. He falsified documentation which lent credence to his claim that this was a party asset, so no, there's no reason for NS to question the appearance of a motorhome, because Murrell had already taken steps to account for it beforehand.