Gravity Skimmer

Hi guys UK Newbie here....oh oh I hear you say!!

Just built my pond.............10' x 6' x 4' deep water level 18" above
ground.....

Having seen a similar pond in action .I plan to use a Central Heating pump
2' below water level..pushing water up to a 50 gal barrel filter
This will overflow to a waterfall and a header pond acting as bio filter 5'
x 3' x 2' This will then overflow via another waterfall to the main pond .Ok
my question .!!can I have a skimmer powered by gravity connected to the
pump inlet plumbing?
Ie skimmer inlet 6" (vertical) oblong pipe in side of pond wall at water
level .to a simple mesh filter box then gravity down to my pump inlet pipe?
The fall of the exit from the pond to the pump is approx 1' although water
is being drawn from a pipe inside pond approx 3' down
Sheesh this is hard to explain but.........will the gravity and the
circulatory draw of the pump be sufficient to move flotsum etc across
surface of the pond?

And yes I have been digging AND laying 1 ton concrete brick blocks (well
they feel like it) in the hottest part of the hottest summer for years
...just so I can introduce my fish....and watch them for 1 week till all ices
over in October LOL!!

TIA for any advice etc

Regards
Chris