New Saddle

I could suggest many, but there's no way my suggestions would be any more valid than the result obtained by throwing a dart at a board full of pictures of saddles in your price range.

Different sit-bone widths, amount of muscle and fat padding, riding position on the bike, type of riding done, rider weight, road conditions and even the way your bike rides factor in to the choices/models that will put a smile on your face.

You're just going to have to trial ride a few models to find one or more that work well for you.

There are shops, I'm told, that will allow trial rides and exchanges, but I have never seen such a shop.

Ask around among your local club(s) and shops to see if there are some used, disused or unwanted saddles for your to borrow and try out or perhaps buy at a low price.

Campybob hit it right on the head. It's trial and error. After 8yrs road riding I finally find my saddle. Specialized Romin Expert.
Hard as a rock to the touch, but the curves cradle my [censored] just right. Go to the shops around you with your bike shoes and shorts an
test some saddles on a trainer. Best of luck

I don't know whether it's available in the UK, but the Specialized Riva retails for $29 USD and it's one of the most comfortable saddles that I've ever parked my skinny, bony ass on. I like it better than the $130 Romin, which I've also put quite a few miles on.

Of course, what my skinny, bony, 60 year old ass likes doesn't mean that your rear end will agree.

There are some online stores that have generous saddle exchange policies that allow you to try different saddles without having to pay for a new saddle each time. Likewise any LBS deserving of having your money should allow to tryout saddles without big costs. Sadly, there is no reliable way to determine what saddle will work for you other than to keep trying saddles until you find that works for you.