Thanks for the reply. I think it is likely I will be back - I have been recommended by folks here to try a range of bikes, but I am struggling to find other products that are as good looking as the Sport, for roughly the same price point. Having previously really liked the Wisper and Urban Mover folders, I have had a raft of people warn me against front wheel drive bikes in the wet, and I am inclined to take their advice!
There is also the Sunlova range but the distributors don't appear to be particularly enthusiastic about letting customers try their bikes - a Saturday viewing was available only after much persistence
Yes, on your Sport I was shown that it has two locks: one for the ignition, and the other locking the battery into place (it took us a while to figure out that's why we couldn't remove it!). Birmingham city centre during the day has a fairly low crime rate, but I'll be locking up in Digbeth and Hockley as well, which are not so great. I think I would take your advice and leave the battery in situ; lugging that around, with a rucksack/laptop as well, is just going to be a lot of hassle.
Without question I'd use a D-lock where I am. I've seen some really solid ones, but unfortunately they cost 60GBP! I will get a tag as well - good idea.