I decided to go for a 3:1 ratio for the front to back sprocket. So I have put on a 48 teeth front crank, and a 16 teeth rear sprocket. This it turns out is a brilliant ratio for the flats, but even on the slightest incline its proves quite tough. I have a constant feeling that I'm in the wrong gear, and I instinctively try and down shift on my gears, which don't exist. In hindsight, I should've done a bit more research on gear ratios, and gone for a smaller crank on the front. This is something I can't change, I guess it will help strengthen my leg muscles.
New wheel ignorance
Since I buckled the wheel from the original bike while trying to get the cassette of it, I invested in a cheap Halfords touring wheel for the rear. Having never had to purchase a new wheel, I hadn't realised that it didn't already come with a rim tape. I happily slid on the new tyre and inner tube on Sunday, pumped it up to 95 psi and rode it into work on Monday. When I returned in the evening to ride home, I found the bike sitting there, all proud and shiny, but with a completely flat rear tyre. An investigation ensued, which is when I discovered the missing rim tape. Lesson learnt !