That's an interesting Twin Turbo you have there, Emma. It's a z1017 and was a co-op exclusive sold alongside the core range z1055 and z1065 in the late 80's. I believe from 89-1990. Unlike the 1055 and 1065, this was very basic - single speed with no bag full indicator or height adjustment. Possibly one of the most basic Twin Turbo's there ever was. But that's not a bad thing, basic works in their favour.

I would give it the full works. At the bare minimum, with all those years of use, it will need new filters, bag, belt and brush strips if you can find them. The brushes will be very worn by now, but Twin Turbo's with a new set of brush strips really clean fantastically.

For comparison, here is the z1055 and z1065. Both are branded "Turbo2" and have the height adjuster on the side and bag full indicator. The z1065 also has variable power.

I've just spotted that it also has a box of tools stood behind it. Hang onto those, they're getting very rare.