That's a very good idea Christy, I actually have two white roses that are climbers but I will probably have to improvise on the trellis (link on an idea of DIY that would allow me to paint the frame purple as the edge of the flower beds http://houzz.com/s/m=7/u=L3Bob3Rvcy8yNjIwMjcz). Thank you Christy, really helpful advice!

Put in a few French drains where you dig a ditch and fill it with crushed rock to help the water drain. In low spots put in some drains [http://www.homedepot.com/p/Tuf-Tite-16-in-2-Hole-Drain-Sump-with-Grate-and-Seals-2HDS-4/203463511] with pipe running to the French drain. You might also need to bring in 10 yards of top soil along with some sand to raise your yard a bit as you're probably right at the water table level. We've had to do all this as we live in the Pacific Northwest in a reclaimed marsh [a nice word for a swamp] where we hit the water table if we dig down 3". We had to put down about 10 yards of top soil along with some sand to raise our back yard. We also dug a French drain along the back to connect to the associations drainage pipes through the neighborhood. My husband has put in at least 3 of the drains in strategic locations around the yard to help drain off the excess water. Our yard isn't perfect, but it isn't the swamp it was the first couple of years we were here. We have to apply moss killer every spring or it takes over the yard. My husband also puts down lime to soften the soil, and help the water drain easier. He and a friend rent an aerator every summer and do both our yards to help with the drainage as well.

I agree re Skimmia, also look at Daphne odora and Sarcococca (both have fantastic scent), Viburnum davidii, Hellebores for early flowers and Astrantia and Geraniums for summer colour. Improve the soil before planting by adding loads of rich compost or rotted horse manure.

Gosh, I've returned after a week travelling for work to loads more suggestions - thanks all! To respond specifically: - the house faces south so gets the lovely morning (and in the uk, sometimes the only) sun. - the husband has avoided putting plants in the planters due to maintenance and they're generally twee so comments here have confirmed to me that they will be coming out - love the idea of wooden boxes with the spiky plants and grasses - also like the concept of taking out the grass/bed/tree in front completely out and replacing with slabs - yes to lightening the windows - to the Barn company, I honestly don't mind the advice and I'd never seen sloping garage roofs. - nicking ideas from landscaping of new builds....great idea! - finally, Helen Scholes, I'm embarrassed about the spelling of kerb. Had no idea! Thanks again all.