At Ringstead you can drop your yak off at the grassy area near the top of the ramp down to the beach & just carry it down the short ramp (at quiet times you may be able to back down -- but not recommended as this is how people get on & off the beach & kids often climb onto from the rocks.
A cart makes the whole experience more enjoyable. Prices in the UK for carts is currently ridiculously high IMHO -- I refuse to pay 65 GBP for what is basically a fraction of a push chair/pram/buggy (UK taxes have gone crazy). Pick one up in the USA if you visit, or make your own. I made a great little kayak tolley recently, it cost nothing - everything was recycled. It was surprisingly quick & easy to make once I started. Here is a picture of it (on the DeeperBlue spearfishing forum): http://forums.deeperblue.net/645421-post131.html