I would be knocking on doors throughout my time in office to see if people had issues they wanted dealing with - why do they think we should support them when they only turn up when they want our votes?
Our local MP does. He's brilliant. He's in his 80s now and sends a newsletter every month. Once he knocked on the door and asked if there were any issues. I half heartedly mentioned that the saplings that had been planted outside were leaning due to storms we had and within the month, new ones had been planted.
I think that going door to door would be a great waste of time that they should be spending getting stuff done. Yes they should be easily accessible and should communicate with their constituents and help them but door to door wastes time.
Given that the average constituency has about 50,000 electors it is unreasonable for an MP to go knocking on doors. A weekly or monthly surgery should be amply sufficient. You can always write to your MP if you have a matter of concern.
perhaps they're in Parliament, where they work? I routinely get leaflets from my MP but they aren't particularly useful. They do tell me how to get in contact, though.