The helicopter seat has been modified slightly with the aid of a bungee strap.  This takes up some of the energy when Harrier leaps off it.  I've been very brave and had a go myself albeit without his elan.  We have concluded that the best idea is to forbid Aunty Biscuit to use it.  She has a chair that she can sit and knit in so she's fine with that.  The white cotton bag was interrupted by shed activities butwork is expected to resume shortly.