I'm not a doctor, and I don't know much about hypertension, and thus I cannot recommend much...
What I can say is, you could start on some weights training too. Start light, but do the compound exercises (deadlifts, bench press, squats). It would be good to begin on an empty barbell. If you are at a ClubFitt gym, you could always ask any instructor to teach you (for free
). This could be in addition to your cycling (do continue with it). Afterall, more muscles = more calories burned during resting periods
Regarding diabetes, perhaps it would be beneficial for you to watch your diet, to focus more on low glycemic index food such that there isn't any insulin spike, but rather, a slower and gradual release of carbs into your blood stream. Food with low GI includes oats (instant one I not sure), brown rice, multi-grain bread from Gardenia (they claim low GI), wholemeal bread, etc.