from your list
1. Full Central Heating system
8. New light replacements and socket and switch replacements.
4. Ceiling Velux window in the extension downstairs
7. Wall conditions prep walls (Plaster or fill) depending on severity, prep for paint
6. Plastering some Ceilings due to cracks
5...
They would double wrap the tank to ensure it's fully sealed before they move it. IMHO it would be far easier making the loft hatch bigger and bring the tank through this opening, not only cheaper but easier.
I have my 405 in asbestos and my advice is to have someone sample it to determine which...