Courgette problems - Virus?

For the last three years I have struggled growing Courgettes. They always present the same problem. The first set of leaves grow normally but after that the leaves become distorted and the fruit is pitted. The plant fails to thrive.
I dig in plenty of cow manure under each plant on the allotment but at home I have the same problem where I only use home made compost.
What is the problem?
See photo's that illustrate the problem

Hi. I’ve had this for the first time this year and believe it is mosaic virus. I took one up quickly as think it spreads easily and I don’t want it to spread to others. Not sure why you get it so often though and hope others have some solutions

Looks like it. I had yellow mosaic virus for the first time this year on my early sown beans and had to haul the lot out. I did a bit of internet research and there are a lot of ways it can be spread or initiated. My beans were from saved seeds and I, mistakenly thought that seeds were virus free but this would appear to be wrong.However I am going to check with my neighbor as he has some of the same growing in his garden if the are OK there has to have been another source of the virus .

Many thanks for your reply. It is odd that it is only my courgettes that are infected. I have squashes planted close by and they are virus free and no other veg is effected. In earlier posts on the topic it is suggested that Beet and Tomatoes can also be effected but on my plot  they are fine.

Exactly the same in my garden only the beans seemed to have the problem.