I got one of these ( arrived today )
https://www.ebay.co.uk/ipp/124819827...2047675.l48352
The 2 xelasticated straps with velcro to fit it to seat were a lot too long ( the two halves of velcro do not align ) but I can shorten the straps by sewing them into a loop, attached PDF is a photo of the pad on my AL7 seat, have not ridden on it yet ( rain due here today ), so will not know if it moves around ( the part that touches the seat is very grippy ) or how comfy it is, but will update after a ride. Pad is about 10mm thick and will at least let air circulate through the mesh.
Update, just done a 90 miler and am impressed with the seat pad, noticed my bum felt cooler even after a few miles, and did not have the urge to shuffle around on the seat that i normally get. Felt 'planted' on the seat and did not keep sliding down to the front. Did shorten straps, and because the front straps line up with the two nylon location hooks under the seat I made up a couple of aluminium ( 8mm x 1mm strip I had ) straps to screw into seat plastic base with short self-tappers and pin the elastic seat straps out of the way. Seat pad did not move at all during the ride, and the roads were nice and twisty....
I would say not at all bad at all for £10.
.