A Geum.

do you mean the orangy/red flower? it looks like a geum. and it would have been growing for at least one year to get to this size. did you leave it to see what it was? tut tut such a risky thing to do. I have some spectacular weeds as a consequence :o))
hope you have some sunshine to enjoy the garden.

Definitely one of the x chiloense type Geums.
If the buds start off yellow with red markings and then open fully to a double bright red flower then it could be a seedling from Blazing sunset, or if just s straight double red then possibly from Mrs. Bradshaw.

Thanks all. And yes, I did leave it to see what it was. Valour is the better part of safety in my jungle. Think it might be Mrs. Bradshaw from your description Boggy. Thanks folks and thanks to the bird that probably left it.

I'd agree that leaving it to see what it becomes is fun (and geums in my experience are frivolous, so cherish them when you have them) but it is indeed dangerous...

It took 4 years for my aquilegia seed to come good. In the same 4 years, native hazels and ferns have become rampant! The camellias are bursting at the seams, the rhododendron is now nearly a tree, the 'bleeding heart' plant is flowering its socks off... All the conifers are rivalling leylandii for offence...

Still, it shows you what likes your garden... (in the UK, I had to weed out 'granny's bonnets'). Here, I celebrate their arrival.