Had two "professional" ones rejected... one from the (supposedly approved) Photo Me machine in Tescos, rejected upon code entry (upload) and one from the Pharmacy, accepted on upload but rejected at a later stage.... so I got the younger not so young lad to take it with his clever telephone and that worked... as Octy alludes to, the passport arrived within a few days once the photo was accepted.
If your vision is impaired requiring corrective lenses it's probably best to remove spectacles - even though the instructions on the passport website state the contrary. I did remove mine for the final attempt, it's no big deal to take them off at passport control points.