As "Folkiedave" may be well "out-to-lunch" at this hour, I'll give Lucy for the time being a quick, partial answer in the words of Mike Harding himself from an interview in Living Tradition No 42 from 2001:

People don't always understand the concept of follow-through, that is people listening to one programme and finding themselves carrying on to the next or people who only tune to one radio station and listen across the whole range of their output. The trick is to tempt listeners to stay eith you and avoid sharp edges where people may decide, without listening, that the next programme is not for them. We get complaints that we should not cater for this audience but but my view is that if you can get people to listen and then present them with ideas, they will take it. We now get up to a million people listening to the show, Perhaps just 10 or 20% are tuning in just to listen to a folk programme, the rest are floating voters hearing this music as part of a whole evening of listening.

So, that in essence is the BBC R2 remit to the outsourced production company, Smooth Operations and if they didn't follow it there'd be no contract renewal and they're all quite keen on hanging on to their jobs. Personally, I find the MH show entirely irrelevant, it tells me nothing I don't know already and it's presented in such an annoying way I see no point in bothering with it. And I'm very sceptical that it "draws in" potential customers to the f*lk trough. In my experience, people who want to discover tradarts are not seeking easy routes or feeling relieved when what is presented differs not a lot from the rest of R2 schlock.