PCR tests entering Antigua from Montserrat

I'm hopefully travelling from the UK to Montserrat later this month. This journey requires passing through Antigua in both directions. I know I need to do a PCR test in the five days prior to entering Montserrat and in the four days prior to entering Antigua. On the way out this is no problem as I can take a test at home and be good for entering both Antigua and Montserrat. On the way back this is problematic. I cannot find anywhere in Montserrat offering PCR tests, and given the tiny population of the island perhaps there isn't anywhere. I'm wondering whether there might be an exemption for arrivals to Antigua from Montserrat – that would make sense as the only way in and out of Montserrat is via Antigua, so it's entirely possible it's regarded as part of Antigua for Covid purposes, but I can't see it stated anywhere. Does anyone know the situation? The tourism offices in both countries have not yet responded to my queries.