Advice On Slow Drip From Bathroom Ceiling?

Hi. I have a strange slow leak coming through my bathroom ceiling. It is a quite syrupy, brown liquid (looks like flat Coca Cola) and it slow drips down through the hole for the downlighter. It is slow in that it is only a couple of drips when it happens and it only happens every few days. Nothing more than that. And I have not noticed this linked to any bathroom “activity”…i.e. It is random, not linked to running the bath/shower or flushing the loo. Above the ceiling is a small empty loft small (you could not stand up in it). And, as I recall, all the water pipes for the bathroom come in / go out at floor level…I do not think anything comes from above. Given the current situation, before I call someone out, I am wondering if anyone could give an educated guess as to what it could be and whether it is something that could be a DIY fix. Please feel free to treat me as a total layman / idiot! And do let me know if there is any more info that I can provide. Thank you - I really appreciate any help and advice.