If your plot has Sphagnum moss growing in it then it is far too wet. You would need to address the drainage. Moss does not rot when dug in,

Are you sure its sphagnum? That's not the usual moss you get on soil that's not been hoed for a while.

Thankyou for replying. I am not 1% sure it is sphagnum. It is light and feathery. Recent hot weather has dried it right up. So, I have been racking it loose, and trying to pick up the resulting debri. Which is very tedious.
Afraid to set light to it, as risk of burning could cause lots of other damage. My next door neighbour suggested, that it might be wise to coat with weed killer, (with a paint brush) to prevent damage to surounding plants. then dig it in. More comments ,please will be very welcome, thankyou all.

There is probably a moss killer that will not kill your plants, ask in the Garden Centres, then just rake off as & when.
It sounds like Sphagnum to me.I get it growing amongst the small rockery plants & pull it out when I have the time tho' I'm not sure that it's doing any harm, just holding some water in( I'm on sand). I don't have it in the open areas though.

Have to say that this has been the worst year I can ever remember for moss growth all over the garden. The drought has severely damaged a lot of it, but it is still there, waiting for the rain.
Normal weedkiller does not kill moss, as suggested there are specific moss killing solutions on sale.
Even then you are going to have to rake it away, it does not rot easily in the soil.

thanks for the advice, will just have to keep "picking " away at it, and after digging through, keep the hoe moving.
My husband used to say " the hoe is the gardeners best friend"thanks again. struggling.

Also check the pH. Sphagnum needs a more acid soil than most veggies and flowers like.

Drainage may be the problem, are you on clay? However if you want a moss free border then you can by digging in plenty of decent compost, do you have a compost heap? Every garden needs one, the next thing to do is incorporate plenty of horticultural grit and work it in, yes in the short term it may be hard graft, but well worth the effort as once it’s nicely dug over and weed/moss free then the use of the hoe is invaluable, all you need is to hoe off any emerging weeds/ moss every other day by doing so you keep your border looking good, it’s all about time and making it so the border does not revert back to moss etc.

Hoe and keep removing it. You're not likely to be able to stop it returning.

On the upside if it is sphagnum & you rake it up & dry it you can use it to grow bog plants like venus fly traps in pots!