Thanks for the replies so far. After being promised a call from an engineer and chasing that up through the night, it still didn't happen. Finally got an email this morning at 9am promising me a site visit but even though I'm chasing it up, still nothing! Don't think the battery has been replaced in my time here (4 years). Do I need to take the cover off the panel and replace? I assume that sets the alarm off again by tamper? The panel is in a cupboard in the utility room which is very dry as the underfloor manifold is housed there. No power cut recently either. Would water ingress in the external siren/box cause it? Thanks.