Hand pollinating sounds like the only way, Wyken. I would also double check your watering, since allowing it to wilt between soaking is likely to damage the stigmas or young fruit, making them shrivel instead of fruit.

Many thanks for reply, Tugbrethil.
Definitely have never been dry. The flowers certainly shrivel. Must be some other reason. Will keep hand pollinating.

The plants look absolutely splendid, strong stems healthy leaves and plenty of new ones to come.

Still no fruit , even with the pollinating? Hmmm. When you feed them, how much potash is in the food? Too little wouldn't allow the fruit to develop, while too much would burn the young fruit. I'm pretty flummoxed, otherwise!

I don't feed them. They are growing in large square containers ( one plant to each ) approx 2feet by 18 inches. Standing on gravel and with adequate drainage.

They are planted in 3/4 garden compost made with mixture of farmyard manure and garden refuse and well rotted. Looks like Christmas pudding ! top1/4 is multi purpose compost.

The plants look prefect. No sign of chlorosis and strong stems and thick leaves.

Do they need more than this?

Well, the only thing that I can think of is to give them kelp meal, or finely chopped dried banana peels. Those will give them enough potash to produce fruit, though if any vegetable scraps were used to make the compost, that shouldn't be a problem.

Am persevering with the hand pollination. Will let you know results, if any. Many thanks.

Hooray! First two fruits discovered yesterday, both on same plant. Now aprox 3cms long.

Congrats, Wyken!!