It's a tricky issue, these bulbs can't be replaced by the user but manufacturer states they are consumables and therefore not covered by warranty.

If you take to the dealer to diagnose and replace you could be looking at hundreds for what should be something worth a couple of quid.

Worth a try asking though for an opinion depending on age of car and relationship with dealer they may offer some sort of goodwill gesture.
 
My car I bought second hand it’s a 2006 seat Ibiza 6l are u sure I can’t get to the bulbs to replace them
You'd test the bulb with a meter. Dirty connections use to get the old style flashers as I recall. Use to have to pull out and push back in. The beauty of LED sealed units these days.

If it's not that stating the obviously, it's a wiring issue. No AI required ?.