I have just spoken to Martin at the Obs and it is highly unlikely that they will be open for residential stays in the near future. With that in mind, I will not be co-ordinating a stay there this year. Our booking is still in place should things change. They are open for day visits but with limited facilities open, you are not allowed inside the main lighthouse but with social distancing (and obviously limited numbers) the patio is open.
I have booked for 2021 for the same weekend.