The Metroneer London EU700 Plus looks ok, but the single speed is going to be a killer if a hill or a strong headwind becomes involved, but the Metroneer EG 1.0 Comp looks far better.
I wouldnt worry about the battery size, my basic E-commuter has the same size and I ‘ve found that fine for a 10-12 mile round trip(Glasgow Battlefield to Glasgow city center) that included a bit of a long hill sometimes encompassing a strong headwind, which seems to take up about 60-70% of the battery.(though I only have 2 gears on mine, so multiple gears would extend that range a bit)
£700 is a good price, but its been at that since mid May, certainly you’ll not find much for that much less and as basic ebikes go it looks not bad
I’ve also a full suss ebike, but finding the basic E-commuter type very versatile and more than capable.