They tend to have most of the essentials, but very little of the 'extras'. Obviously most things can be ordered, but that can take upto a couple of weeks to get unless it gets flown in from guernsey.
If it's standard items such as fuel or oil filters for inboards then they'll probably have one in stock that'll fit, but if you need a prop or a new chartplotter, then you're going to be pushing your luck. Nuts, bolts, antifoul, rope, oars, lifejackets, batteries, small outboards, bilge pumps, flags, bulbs, switches etc are generally in stock.
__________________
|