Has anyone got a suggestion for a clematis which likes a dry bank that is available in the UK?
They don't like being dry,unless you are going to water them every day and the toughest would be a montania but I think its not the right spot.
clematis tangutica is almost drought proof when established-rampant though so give it space-it will also self seed-yellow pendulous flowers and possibly the best seed heads
If you can dig a big planting hole and sink your new clematis very deep with plenty of moisture retentive garden compost and well rotted manure and then keep it watered and fed for the first couple of years (and protected against slugs) you should get something tough like a viticella Etoile Violette or the afore mentioned Montana and tangutica to establish but you'll also need to train their stems to avoid having just a messy tangle.
Thanks for the suggestions, I've decided to sink a large/deep plastic pot into the ground and plant within the pot, so I can control the moisture levels and nutrition. The spot is in competition with leyllandi hedging (neighbours) and an ugly fence so I'm having to be creative to cover the fence.
A plastic pot will be too restrictive for clematis which likes to send its roots deep. Much better to let the roots spread out and find food and moisture at their will - and they will if you get the initial soil preparation and watering right as indicated above.
I forgot to say obelixx, the bottom of the pot has been cut out, the soil has been improved, the pot is there to allow feeding before it can dry out and the leyllandi can soak up all the moisture.