Guildford Cathedral - Asbestos Removal

My brother in law, Adrian (Adrian Cox Associates) is a structural engineer. Guildford Cathedral has a bit of an asbestos problem with apparently a layer of acoustic asbestos sprayed over the ceiling and walls. Clearly this has to be removed. Challenges to this include: 1) public access and services to continue through out the removal works; 2) Minimal holes in the walls; 3) No holes in the dressed stonework. So the ceiling has to be sealed off from the body of the building. This is achieved by building a temporary floor below the ceiling. The most major problem is where the transept crosses the nave where there is a span of 19m (due to not being allowed to cut into the dressed stone). To achieve this Adrian has designed 4 vertical ties which can each carry 6 tons (so 4x6=24 tons in total) to support the temporary beam and floor). Each tie is held in place by a  200m diameter x 250m steel lined socket. You can see the ties and beam in the main photo. My additional photos show the nave of the cathedral with some of the falsework in place and secondly Adrian.