The bike I normally use is a Halfords Carrera Luna bike from when my eldest outgrew it. I'm not a serious cyclist and only use it occasionally to get from A to B, whether that's just for nipping into town or cycling to the start of parkrun.
My problem is that it never feels very fast when I'm cycling and I struggle on the inclines. I don't think I have averaged any faster than 12mph for the 5 mile route I do, which doesn't involve much traffic.
I am by no means unfit, having just ran a marathon a couple of weeks ago and I normally run around 30 miles per week when I'm not training for an event.
However, I still want to get faster cycling but don't know where to start.
Any ideas, please?