Buddy: Return postage was £6.95, Special delivery. If you want full insurance for the cost of the unit then it doesn't get any cheaper because the add on insurance will eat up the cost savings (Checked out a number of parcel sending options, f**k, i'm tight!

).
I only sent the physical box back, whereas you'll be sending back the box and the harness, but the threshold size to jump up another pricing tier is bigger than the box your set was sent in, so it'll be the same price.
Special delivery insures up to £500 and guaranteed before 1pm next working day (not on a Saturday).
Looking at yours and other people's returns, I think V-power is really screwing up my mpg - costs 6% more and maybe giving you 10% less economy. If I were to get 47mph with regular Shell, that would mean V-power costs you 17% more per mile than regular.
I used Eco mode for a while and did absolutely nothing for me. If you want to drive with a feather foot in Sport or use medium throttle in eco to get the same effect then the mpg is the same in my experience. Town driving is when I need the power - some roundabouts in Newcastle (most notably "4 lane ends" on my commute) are insanely busy - you really need to put your foot down when you see a gap and take it.
Going to run out this V-power and brim with regular Shell.