Perhaps in light of the expenses crisis the assumption is that most MPs actually work for themselves anyway; this would be unfair as many do a good job as servants of the constituency. They promote a range of local causes as well as defending individual and group rights and taking cases to councils and beyond. They also act as advisers and give weight to campaigns. It is said there are divergent levels of service, with those MPs who enjoy safe seats being more relaxed about their presence locally and those in marginal seats being very keen to be seen as the defender of all things local. But the key thing here is being seen. Many MPs in safe seats so the same job as those in marginals, they just don't need to shout as loudly about their work.
Often representativeness of parliament is linked to the age, gender and ethnicity balances, while some predicted parliament would be younger, more feminine and more representative. This was not the case, with only a 2% increase in female MPs. But does that matter? While there perhaps should be a 50/50 split, with the geographic link it would still mean one-sided representation at the constituency level. The big question is about feeling represented. There are a range of value-laden 'should' demands of MPs in terms of how they should act as representatives (beyond expenses and all that relates to that type of behaviour), but many of these are quite unrealistic for any individual MP representing up to 100,000 people while also having a full time job in parliament. This puts the onus on the represented to go out of their way to be 'represented' and so show they have power; but in turn that is impossible if everyone actually did simultaneously demand the time of the their MP. MPs are not the only route to representation, but the fact that they are the formal democratic link places a burden upon them.