It's Royal Mail's fault. They charge extra for free stuff now, so most magazines have stopped including them for subscribers. My wife used to get loads of Women's mags- which I'm told have loads of freebies. She stopped all of her subscriptions when she found out.
I hate Royal Mail. I work for them. Every several weeks they change something else which makes it worse for the customers and us employees. Within 5 years, customers will only get mail 2 times a week, it will cost loads more and you'll have to collect packets from the sorting office.
I'm sure this is a statement of the bleedin' obvious, but, they're not your friends if they would grass you so readily. Perhaps it would be a good idea to use your new year's resolution to find a better environment to work.
Do you hang out with these people outside of work? That would be terrible for you as a person. Don't do this to yourself. Life is too short.
I wonder if you're going very fast on these runs? Something tells me that you probably are. If so, slowing down a bit would make going longer seem less daunting and more 'doable'. As a guide, you would want to be going slow enough on your longer runs, that you could still talk- at least a sentence at a time.
I would advise changing your routes, etc, as much as possible. Where I live, there is little variety of running routes (London, near Heathrow), but I mix it up as much as possible. If you could take in a bit of off road- that would be great. Run one night a week with a club, or with a friend/ partner. Maybe just run 3 times a week, doing a different sport instead of the 4th run. Whatever you do, mix it up. Otherwise you will eventually run out of enthusiasm for running.
I don't think it's enough to be honest. 2 runs is a minimum, but 3 is considerably better. It's the mileage that's the problem. I'm doing London (Yay) too and am up to 12 miles on my long run. I certainly wouldn't want to be on much less by now. You do need at least one long run around the 20 mile mark, a few weeks before race day and the problem there is building distance up in time. Whilst I tend to increase quickly, common wisdom says to up your distance by no more than 10% per week. At the moment, that's only 1/2 a mile a week increase for you.
I think Johnny C may be onto something with a run/ walk strategy. It might be a way of building up your long run quicker, but obviously such a strategy comes with an increased risk of injury.