Longhurst last seen at ITV Westcountry, though suspect he's not there any longer. Infamously "fired" from Sky News thanks to an incident involving Owen Jones (who later denied it had anything to do with him after he walked off mid interview though it wasn't the first time and it wouldn't be the last time he did that) in 2016.
Before Sky News he was a presenter of BBC South Today, he suddenly left there too, without an on air mention, the local papers claimed he was doing voice over work for radio ads, which they (the BBC) 'frowned upon'
Mark Longhurst wasn't at ITV West Country for very long (possibly only a few months, maybe a year at best?), and similarly disappeared without warning. No idea why. I was unaware of Longhurst's existence, prior to his joining ITV West Country. I found him a very staid presence from the outset, and there was also zero chemistry with his main co-presenter Kylie Pentelow.
I therefore thought him a very poor replacement for his predecessor Ian Axton (who in fact was the very person that would have hired Longhurst, having ceased anchoring in favour of an off-screen role as Head of News at ITV West Country).
I was glad when human-form-of-beige Longhurst vanished, and that the main male anchor job ultimately went to the well-deserving Jonty Messer.
Messer had been the predominant temporary male anchor (sharing duties mainly with Bob Cruwys) for a period in-between Axton's departure from on-screen duties and Longhurst's debut, and again after Longhurst's sudden disappearance.
I always felt that outsider Longhurst being hired in the first place was a bit of a slap-in-the-face to the well-established Messer, who always seemed to me like the natural choice to replace Axton.
The day that it was announced on-air that Messer was now the official/permanent/main male anchor, the average viewer probably thought that he'd already been that for weeks/months anyway!