Bosch Rotak 36 Electric Lawn Mower

I was looking forward to this bosch rotak 36 lawn mower after reading good reviews but was so disappointed when I attempted to mow my average town-garden lawn. I simply found it such hard work to physically push. The cut was fine and the mower easy to assemble. Hopefully, this was a design fault on this particular mower (it was in fact a rotak 40) but I feel particularly frustrated because I returned it to Homebase and when I asked if it would be returned to the manufacturers, they said it would just be put on the skip! If there is a fault, how much landfill space will be taken up by these new mowers?