In answer to the first part - they got on TV like most do through connections, Gabby's dad was a famous footballer, Terry Yorath, and Dawson a rugby international. Gabby did start in local radio before Sky, but some committee seems to have picked out Dawson as a future star much as they picked out Gary Lineker and invested in him.
I quite like Gabby Logan; there are a few nonentities I'd fire before her - notably Shearer, but though Matt Dawson doesn't particularly annoy me, I remain very irritated at how easily he got prime time on certain TV shows without proving anything at all. The one that stands out is Channel 4 Racing where you have top professional presenters, steeped in the sport and you had this idiot (in racing terms) come in and seemingly take over The Morning Line. The quote at the time was this:
""Dawson's limited racing knowledge when he interviews Nicholls and Tony McCoy in the forthcoming weeks will attract flak. But the key will be the reaction of viewers and whether or not they choke on their cornflakes.""
Well we all choked and Dawson disappeared, but like Christine Bleakly he must have a contract so he pops up here and there.
Tufnell annoys me just as much as Dawson in that he has no discernable talent, but someone years ago thought he was a bit of a lad so would be a good signing - the Beeb clearly has too much money.