It takes him 40 minutes to talk about one stone - so I would imagine a documentary by him would take about 5 hours.
I'm baffled as to what the method is behind this madness - but it won't be to reduce the amount of calls into the call centre. The call centre also handles the calls for Jewellery Maker, Hobby Craft, Sewing Street and Gem Collector too - so I would imagine the call centre is constantly busy anyway.
I just think it's a way of having to justify their salaries. It wouldn't make sense to retain Dave, Toby and Jake all year round just to go to the occasional trade fair and / or mine to source stones - so in between sourcing stones, I suspect they throw them on the telly to give them some work to do.
They didn't need to worry about that when Steve was the one sourcing stones because he owned the company - he wasn't taking an extra salary.
I'd have shown them the out of the door, along with Colin, to save costs rather than axing presenters.