I've just joined this forum myself and your post caught my eye as we're also in Hampshire and work for a number of landscaping companies delivering their leaflets. (We're in-fact based in Farnborough- at the North East of Hampshire, where it borders both Berkshire and Surrey.)
To say something productive here instead of just hello;).. when you're thinking which new areas to expand and promote yourself to, have you thought of using satellite images such as those on Google maps as a first step? It's just that this is a great way to recce new areas and narrow down your choice very quickly and cheaply (without you having to drive around the areas, which would probably be the next step ) and it surprises me that many of the guys we work for haven't thought to do this, especially in your business where you'd be looking for 'green areas' with bigger gardens and trees I guess. Just a thought, if you've not already had that thought- and good luck with your 'expansion'. Regards, Warren, for The Extra Mile Leaflet Distribution.