Cargo Bikes

So I’ve got to the point where I now have the money ish for a cargo bike (£2000), but I have a bit of dilemma. The bike’s going to be used for taking my daughter to and from nursery 3 days a week and then on to work for me. It’s about 18/20 mile round trip with the nursery at about the halfway point, there are a couple of hills but nothing major. It’ll also be used for visiting my parents which is a 30 mile round trip down the coast, very flat and for the weekly shop as part of these trips.
I’ve narrowed down my options to either an omnium or a Larryvsharry. I know this is way more bike than I need, but not wishing to sound like too much of a twat, I have my image to consider (ageing want to be courier) so there’s no way I’m using one of this plastic chairs people attach to their ugly hybrids. I’ve also discounted any kind of trailer as I don’t like there position on the road.

Narrowly I think the Larry is my preferred option because of lower centre of gravity and the greater flexibility in terms of the type of baby seat that I could use in the load bay. I have reasonable wood work skills so I’m assuming that I’ll be able to build my own box given the price of any of the larry accessorises.

So the crux of my dilemma is can I get away with running the Larry singlespeed. It’s the only way I can make it work money wise really. I consider myself to be fairly fit and I intend to stay that way. I’ve only ridden fixed for the last 10 years and my one geared bike hasn’t been ridden in years. So I’m concerned about the maintenance of gears, which I can do, but I’d rather not.
Other than the frame and fork the only other stuff I would need is a front wheel and some brakes, everything else I have.

So an SS Larry, how silly is that idea ?