Probably an unrepeatable offer but the water board for my previous house offered to fit water meters for free if you told them that you were a heavy user of garden sprinklers.
It sounds wierd - giving a freebie to the most profligate water users but maybe the idea was to tempt them into getting one fitted, only to have to curb their usage when they see the actual figures.
I agree that 2 persons, no kids means light usage but you mentioned garden sprinklers and I'd need to think about it before I'd give the meter the thumbs up.
Maybe run the sprinkler at your usual setting into a 5 gallon bucket and time how long it takes to fill. Work out how many buckets per hour, then
44 x 5 gal buckets = 1 cubic metre
If the price per cubic metre is not shown in your bills, because you're not on a meter yet, it won't be to hard to find out online or by phone.