Try one or more test shoots ahead of time.
Since you have sufficient time before the wedding day I recommend trying some test shots at the same time of day as the scheduled shoot under both sunlight and overcast sky with stand-ins, such as friends, family, street urchins, or whatever you can find. That will reveal lighting and composition problems.
Overcast will require at least some supplementary light if youíre to get pleasing color. Thatís often advisable even with scenes that are frontally lit by sunlight (balanced fill flash to lighten up eye sockets and other facial shadows).
If the sunlight falls directly upon their faces then that will irritate the eyes of the wedding party. In that case youíll have to select an angle so that theyíre not all squinting uncomfortably in the blinding sunlight.
If you have enough stand-ins, that will guide you to an effective composition. It looks like a lovely spot. The composition options would be greater if that bench were gone. You could examine it to see if it might be reasonable to request it be temporarily removed for the shoot. If not, then youíll just have to make it part of the composition.
Donít overlook the possibility of altering your camera angle to just exclude the bench. Youíll likely want some shots that include and some that exclude the bench.
Depending upon the focal length of the lens and camera position you might try a composition that puts the entire wedding party just in front of the bench and, therefore, obscuring it. For this shot you might even temporarily cover the bench with a camouflage cover that matches the grass and so forth behind. In this way even if a small part of it is somehow visible between legs and such it wonít visually clash nearly as much as would the white paint of the bench.