mine used to be silly like yours but changed Broker 5 or more years ago and im covered for 5m public liability 10m employers, 100k hired in plant, my kit upto 50k 1 piece, 150k max contract cover, legal etc cover 3 employees, gone up this year so its about £1600 but id set limits of max depth 2m etc as we don't do much deep stuff anymore.
huge list of exemption and requirements though
fleet policy is more but covers 10 vehicles including 3cx and Telehandler for road, works out about 1k a vehicle
20 years no claims and must have spent 50k on insurance or more, touch wood