Get a bird watcher's spotter scope. They are effectively half of a decent pair of binoculars. Aldi had them a couple of months ago for about £20 - will cost you 5x that for a "normal" one. Ideally, you want 7x magnification and 50mm object lens like good marine bins, don't exceed 10x as you will not be able to hold them still.
The pistol grip idea is excellent, you will get that from any camera shop and it will fit the tripod fitting in the base.
-------------------- Boaty junk clogging up your shed or lockers? Chuck it in Marinaskip