I can't see the problem in planting out now. Autumn is the normal time for planting but we're nearly at that point now.

Plant out now with as much improvement to the soil as you can manage and water well both now and in the weeks to come.....there should be no problem. Are all the plants in your pots full hardy? Something to bear in mind.

Don't forget to gently tease the roots out a bit to help them strike out. planting holes need to be bigger than the rootball. half as big a again if you can. then mix compost with the soil and use that to backfill round the plants.

And enjoy your new garden!

Its still very dry in some areas (? Hampshire) I would leave it until the end of September, but stand the pots
where the plants will eventually be permanently, to make sure of the right places.

Thanks everyone - that's really helpful. I'm on the south coast so should have time to get this right - off to start digging the garden over now!!