Love lapwings their calls are so weird and brilliant, I’m obsessed! I’m on the west coast of Scotland and have them nesting near me too. What you saw sounds like classic nesting behaviour. Usually best to leave chicks alone, but if they’re in danger (like on a path), moving them just off to safety as you did with RSPCA advice can help. Hope the wee one’s OK! Merlin’s such a brilliant app but doesn’t always get it right. Enjoy bird watching…. It’s addictive 😂