One of these:
https://www.carradice.co.uk/bags/saddle ... saddlepack
Used to use it on my commuter, but been gathering dust in the shed for quite a while now.
Absolutely bomb proof and nicely retro looking waterproof cotton duck fabric.
About 6litres but the ‘flap’ if pretty big and you can over stuff it if needed. Sways a bit more than a bikepacking style seatpack but was never an issue on the road. Had a weird extra strap you could loop round the seat stay which I took off as it would only reach on a bike with a tiny amount of seatpost sticking out. Some wear where it rubbed on the seatpost clamp bit nothing serious.
Can email photos if you want.
£22 posted?

Hi Al, this maybe what I'm after for my road bike, can you email pics? james.olsen.remote at hotmail.co.uk. Ta.
Does it strap down fairly tight on the seat rails? I just need something to keep a summer sleeping bag and bivi bag dry really, so not a lot of weight going in it, just bulk.

Is this still available by any chance

I bought it, sorry firestarter .. will let you know if it's not right for what I have in mind though.

No worries mate cheers

Sorry, posted it to mr Olsen this afternoon.

No worries mate cheers

Firestarter, it's not quite working for the kit I intended it for - happy to pass on to you for same price, posted? Cheers, James

Thanks mate

Recieved today many thanks Jameso and Al