Now fully open - beer offering - cask seems unlikely. Indeed having now been assisted in the search, the beer range at opening is shown as: Peroni (5.1%), Salt Jute Session IPA (4.2%) and Lucky Saint (0.5%). All and any info welcome. It does open for breakfasts. Probably fair to say food focussed.

htps://www.camdennewjournal.co.uk/article/who-says-its-all-over-for-pubs-as-rosslyn-arms-to-become-oak-poppy

Planning permission was granted in July 2013 for the demolition of the existing single storey additions at rear ground floor level and covering over of rear garden and associated roof works including the installation of 2x air conditioning units and roof lights on new roof and flue pipe to rear elevation. Erection of timber screen to side elevation. Refurbishment of shop front including installation of new awning, new halogen heaters and up lighters.

It last operation was as below - as the top article says, this was far from a success!

A new all-day brasserie inspired by the cafe culture of Tel Aviv has opened in Hampstead, north London. Café Hampstead has launched in Rosslyn Hill on the site of the former Rosslyn Arms pub. The ground floor has 50 covers while the first floor has a cocktail bar that can accommodate up to 40 guests.