The quoted electrically assisted range of around 30 miles is adequate for my use, but I looked up the Halfords site to find more about a spare battery - and was disappointed to find that none are currently available
I don't have an E bike yet but when the time comes a spare battery would be very handy to have on charge while I am out cycling, hopefully by that time electric car charging ports will be common and adapters will be available for E bikes so the charge can be topped up whilst shopping etc.
I, also, was wondering about electric car charging ports - but I didn't find any useful info. Clearly a simple 13 amp socket would attach to my charger - but it would be a long wait! However I found an article by a group who had toured GB in e-bikes. They each had a spare battery, and at the end of a day's cycling they usually found a campsite with a 13 amp socket, and on rare occasions where there was none, friendly neighbouring houses charged their batteries overnight. Currently I have no problem with a single battery - If I stray too far from home, I can phone my wife to pick me up in a car (with the bike folded in the boot). However next summer I may be straying into areas inaccessible by car, and a spare battery would provide some comfort!
I do not wear a helmet when cycling but I would have thought that all cycling jackets have a hood which will fit over a helmet, and some mountaineering jackets are designed with a hood to fit over a climbing helmet. Otherwise a thin but windproof balaclava type thing might fit under your helmet.
I have currently abandoned the thought of using a cover for my ears. I have yet to find a satisfactory rear-view mirror, and my ears are the best indicator of traffic arriving from my rear. So although I am equipped with a hood - I don't use it on roads, but I certainly will use it along traffic free cycle routes if the weather deteriorates.
On a more general note - I think an e bike is a good idea - not only for septuagenarians like myself. The assistance only operates if you pedal - so it provides some useful exercise for the lazy, but even if you are reasonably fit, and want more exercise, the assistance can be saved for hills and head winds , so making an outing much more pleasant.