I have just contracted my one and only builder and he has come up with a method of sinking the jam jars into the back wall and curving the top of the structure which should look great!
My other builders are my dad and my husband as well as a merry band of volunteers! Not exactly Chelsea style but it will work I am sure of it!
Oh, and in case you were wondering, Andy Sturgeon is a genuinely lovely guy. Very personable and easy to talk to, he discussed my design with a keen eye and made some helpful suggestions in terms of finding show quality plants...lets' hope he is right!