Footling about in or near the City Zone in a single was discussed on a couple of threads about a month or so ago, with a rough consensus emerging that a floatplane would come in handy, as a splashdown in the Lee Valley Lakes could be the the best option. I don't think I'd fancy it, as it seems to me bad enough flying the east-west between Elstree and North Weald/Stapleford, especially at the Rule 5 notified bit where you have to duck down under the lowest bit of the Stansted CTA. Lots of houses, some quite dense woods, a few dodgy looking fields. A bit more open to the north of the M25, but then you'll bump into someone looking for BPK, or get biffed by the mad farmer who aerobats his Yak around there (seem him twice, more worried about the times I haven't seen him), so you can't win, really.