The Propellor Inn, which is on Bembridge airfield, behind the gliding hangar is OKish, with big portions of fairly typical pub food.
But if you can make time to climb the hill to the monument, then turn right and follow the coastal path all the way into Sandown (about an hour's walk each way?) there are plenty of restaurants there and its a really glorious walk.
Alternatively, there is a pleasant beach about twenty minutes from Bembridge...the tower will point you in the right direction.
The walk into Sandown town from Sandown airfield is less stimulating, being along suburban roads, but much shorter.
There used to be an aircraft museum at Sandown that was worth a visit, the other side of the runway from the "cafe" but I am not sure if it is still open.
W