I'm new on this forum, so please forgive me if my reply sounds a bit out of place. Anyway, let me share a similar incident that happened to me with French doors. A few months back, I misplaced my keys, and like you, I was worried someone might try something sneaky. I didn't want to take any chances, so I decided to change the locks on my wooden door. But then, I thought, "Why not consider
UPVC french doors this time?" They have a great reputation for security and style. As for the cost, it can vary depending on where you live and the type of lock you want. But generally, changing a lock shouldn't break the bank. I suggest reaching out to a few local locksmiths for quotes to get an idea.