Will the sebo rep have any info on demographics around your area though? Would the shop +30 miles be the sort of place where a brand new spiffy vac at it's cost, then a 4 year maintenance contract for £x, including bags when needed, and a filter for every box of bags, new brushroll every year etc be possible? t's and c's apply of course.
You could roll the dysons in with it, and have a cost menu, so £70 plus £50 gives you an as new dc07 with a 4 year maintenance pack (so filters every year, belt every 2, 40% off any fixage etc), up to £250 for an X1.1 (so undercutting JL http://www.johnlewis.com/sebo-x4-automatic-excel-eco-upright-vacuum-cleaner-blue/p1707684
, not sure what cost you will get them directly for though), plus £130 for the 4 year package, then everything inbetween?