the thing with a diy gutter vac is that you need the suction power as if you don't have that then its money wasted.
IMO and experience you need more than 3000W of suction power especially for well soiled gutters with large chunks of turf and plantation frowing out of them.
the one from Eastern trading on ebay for £499 looks not bad but I havent tried it so cant really recommend it, I bit the bullit and bought and Omni-vac for £1500 as it has 4200W suction power and it has more than paid its way and it even lifts broken tiles and slates from the gutter.
as for that Darlek on acid for £1999 on ebay I would defo exterminate any idea of buying that contraption from yet another wide boy trying to rip people off.