Is it the fuel sender unit?

[Greg71]

Hi,
for a couple of months now, my 57 plate mk7 fuel gauge goes a bit crazy. when it gets to about a 1/4 tank, as im driving along, the gauge will very slowly start to drop, as does the predictive miles to empty readout.
As it gets down to about 10 miles remaining, the numbers keep flashing alternately with 4 dash lines aswell.
I know there's fuel in there, as its usually a true reading when I set off.
Is it likely to be the sender unit in the tank?

cheers guys.