Hi Neil - Depends whereabouts in Manchester you are! If I were you I'd just avoid the main arterial routes and stick to the back roads for a bit. And take it easy.
Saddle sores, as Steve says, disappear after your butt and saddle get more intimately acquainted. Usually because your 'underneath' toughens up somewhat. So yes, it's something that you have to put up with in the short term. But there are a few factors to consider: type of shorts, whether you prefer to wear underwear (usually causes chafing), type of saddle, riding position, and how delicate your bits are. For example, I just can't get on with padded shorts - or padded undershorts. It's like wearing a nappy and they make my goolies too hot! Also, one saddle may be like sitting in an armchair for one person, and pergatory for another. Remember, if you go for padded shorts, it's best not to wear anything underneath.
Like most things cycling, it'll take a bit of trial and error (and outlay) to find the right mix of 'ingredients' that you find works FOR YOU. In the meantime, you may also need some @rse lard in which case Sudocrem is the cheap and effective remedy usually recommended by fellow CC'ers.
My all time favourite CC quote: Slap it on and smile!