Haha I myself also have the same issue with Public riding and also owning a bike i've never actually used!! seems to be the norm
Perhaps watching some stretching videos and just join along with them in the morning before work would give you some benefits ? even firing up the muscles with a stretch can give you that little boost towards burning the calories, as you become more active your mind will adapt and you wont have this tired feeling as much after work it takes awhile but once it kicks in you'll make it part of your lifestyle and wanna do it.
There's a website i use and really only buy the chicken from there but there's plenty of other useful meats you can buy and it's delivered to your door in a freezer pack fresh not sure if you'd want that but it's 5kg of chicken for £25 i normally just get a tub of that and Buy as much fresh veg as possible in bulk from local markets if you head to Google and type in "MuscleFood" you'll find the link easily enough
There seems to be a lot of people located in London joining the forums lately maybe one of them will show up sooner or later and get more involved maybe set up something local.
One thing i have to say and get out there is you shouldn't feel ashamed or awkward about anything you do that involves making yourself stronger and more active, when i first started i decided i wasn't gonna go to the gym until i lost a little more weight.... Kinda kills me now as i have realized the gym is a place to get fitter and more healthy and no one is there to look or judge me.. we're all in the same boat.. and i'm sort of going into a random rant and i'm sorry xD
*Rant over...
Either way if you need support or you're looking for more info you know where we are
*Rant over...