Sure have.
The canvas frmo GoWesty in the US is sailcloth and therefore waterproof and won't mildew - ours got wet at the Pre Xmas bash at The Duke and put it away for over a week, popped it up on a dry and windy day and its as good as new not even a hint of a damp smell.
It was very cold at night that weekend as the heat passed straight through the canvas, but have now invested in a Baxter's Bacofoil Poptop Wrap and an Eberspacher as of this afternoon so am expectign to be toasty once I can fit the Eber. Also have a very nice set of JK window thermal mats which should also help.
You are never going to beat the Mr Whippy's of this world in the hermetically sealed fibreglass bubbles, but at least you will be able to go into far more car parks
