What about those plastic Tarpaulains that you get from the junky shops or car accessory shops. You would have to put some sort of silicone sealant around the seams, but the better quality ones should stand up to a fair amount of use. They are also used as paint dropsheets sometimes.
have you tried looking for offcuts? I got a decent sized piece of spotty vinyl like this, used it for a tablecloth - would have got two or three cushion covers out of it I should think. It cost about £1.
TBH, I might be tempted by an 'easy to dry' option as waterproof is hard - or wrap foam in pound shop shower curtain and glue/tape it, and then make a cheap fabric cover to make it more appealing / comfortable?
<sigh> I tried a shower curtain, but its too flimsy to work with tbh. I've looked for those outdoor table cloths, but I've only found one that's big enough for one and its £25! Too much, for a novice like me to screw up! I think he may be resorting to Option B, which is two faux leather cushion, just for the maiden voyage, at least! Its just for the outside seats, which he reckons may be a bit uncomfortable if he's sitting there fishing all day! The cabin ones are fine. After several washes, they look and smell like new.
I might come up with a plan at 2am, I usually do! For now though, I should concentrate on the fact that we are going away tomorrow pm and I haven't finished the washing yet!
Thankyou lovely ladies. I've been given a small reprive too. we're not going til Friday morning now, so if I get my sh*t together tonight, I can go on a mission tomorrow. Tomorrow, just happens to be market day too! I'll let you know!