Other posters have suggested ways to raise money or to compromise with cheaper options in the interim.
My advice to the OP would be to leave your pension alone so that it can mature. It sounds like a private pension, so there are likely extra costs involved in taking out your 10% at 55 (and everything else). You will probably be penalised far more than the 10% anyway by the time it matures. You might be grateful for it in later years.
N + 1 is a wonderful thing but so is self restraint, making do with less costly options as others have advised. I could understand it if you were buying a house, but any bike will eventually be worth a goldfish and a balloon so where will the next one come from? It seems strange that the preservation of your health won't happen if you ride about on a nondescript bike, but miraculously will if you give up a chunk of your future pension to buy a brand new one.
Type 2 Diabetes is no joke, but most sufferers do manage the condition successfully in the long term. The health conditions that the OP mentions are not inevitable, despite the curious sense of entitlement that seems to arise from mentioning their possibility. It's a sad fact that as we get older, many of us will develop ailments and afflictions that we have to learn to manage. We might not like it, but that is how it is.