Can anyone tell me if this is an evening primrose please.
It certainly is -- what a beauty!
Watch it over the course of an evening and you'll see it open. Oenothera biennis.
grice38 - you have a classic collection of typical British self seeders. Nice mixture. If you are not into aggressive control you can garden by merely removing really weedy stuff and anything you don't like the look of. The rest will look after itself. Lots of wild life value.
floral_uk thanks, Its taken 2 years to unearth most plants, garden was so overgrown when we moved in. The bees and butterflies are loving it: