Help! Why does my rose do this every year?

[Ddakji]

I have what a I believe is a peace rose in my front garden, planted, so I’m told, just after the war.

It used to flower beautifully but in recent years it seems to almost rot as it flowers, with the petals curling back and sometimes not opening properly at all.

Does anyone know why it does this and what can do about! It’s an easy-facing garden so morning sun.

I’ve attached a couple of photos showing the “rotting” blooms but also what it looks like when it’s doing well.

Thank you!

David Austin have an excellent advice line for roses, and they do good roses feed too.

Judging by the anecdotal evidence from my own roses, they tend to do that if it rains a lot just as they are coming out.