I am in DB camp for wearing shoes then getting on bike, I just know I would make a complete fool of myself trying to do what the elite do. At my speed it would not make enough difference.
Mrs L, as MC says you can just ride your bike as it is. Bikes wheels seem to come in 4 sizes from what I understand and some hybrid bikes will have the less common size hence the limited options, save your money for now.
If your time was slower than 5:18 I might be willing and able to go through The Times newspaper results listing. However the newspaper archives maybe quicker. Or just go to the million marathon runner t shirt website and find out there.
Mrs L, changing the tyres on your hybrid would mean swapping to a road tyre rather than a mountain bike style tread pattern, it makes it easier, but the size would be the same, so first look on the side wall of the existing ones and then speak to the local bike shop or back here for further help.
Durhambiker, shame you didn't do the sportive but if the weather was anything like down south it would have been hard work, plus at least you got a decent run done. All the best for the DIY weekend, with the pirates.
HIgh5 Isogel does not need water as it is a watery gel, best to try it out in training. I find gels too much faff and chomp on Clif bloks which means I resemble a hamster for a few minutes and then swig electrolyte drink to get the remaining bits off my teeth.
MC, you are being very sensible as nothing can beat being a close family and everyone will need support at some time, including you. If I can give a hand please ask.