There will likely be a big cost for the licenced removal company to make the enclosure in any case. If route is via the house, then the cost is largely the enclosure and removal, and potentially making good any decorations - so mainly the asbestos contractor work. If the route is through the roof, then there is additional cost for a scaffolder and a builder to access the roof and keep it watertight.
The OP needs to get it looked at by an experienced removal firm, and take advice. Bare in mind that an experienced independant asbestos analyst firm will advise on more specific health and safety issues that the material might present, and this might be better initially that a removal contractor's advice - as any removal contractor has a vested interest in the removal work.
The OP needs to get it looked at by an experienced removal firm, and take advice. Bare in mind that an experienced independant asbestos analyst firm will advise on more specific health and safety issues that the material might present, and this might be better initially that a removal contractor's advice - as any removal contractor has a vested interest in the removal work.