BCA will def charge you and find that. I had a bad experience with my
Ibiza, (but a good experience with the Leon, where there were obvious dings that could have been argued both ways) the inspector must have xray vision and used the squiggly line thing, onto reflection which for the life of me, could not see even if I spent 10 mins looking. My mistake was I only brought 1 set of keys as it wasn't collection time yet, so I left him with the car for a good 5 mins, though I can't prove it, I'm sure he put the small dent there. Maybe they get comission finding damange. So he levied a charge of £35 per panel. Both panels were the back panels on the SC (image attached). Luckily the guy used a tablet camera, and it wasn't really clear, I used my dSLR, and still couldn't find it. I told him I couldn't see it, and what if I disagree, and he reponded, that's why I'm one of the few inspectors left. He did warn me (maybe to deter me) that if I contested it, they would look at it, but the would also look under the car if there is any damage too (WTH). In hindsight, I would have brought along the fair wear and tear booklet next time. I contested it, and head office said no charge as they couldn't see nothing from the pics! On other non-seat topics, I'm due to return my Volvo V40 end feb, penalty for missed service fixed at £120. Cost of service to avoid the penalty, £285...sooo guess which I would take?
There's a place near Hendon station if your located in London that probably can fix this for around the £100 mark, I did fix a scuff on my
Ibiza there, and that xray vision BCA guy could not find that.