There were four people, one was station staff wearing a hi-vis orange vest, which I know is acceptable, another who I presume to be a delivery driver was wearing a yellow vest, not acceptable, and the other two were wearing no PPE and looked like SSP staff.
As I didn't see the member of station staff using a telephone between trains I highly doubt there was a line blockage on.
The crossing they were using is a barrow style crossing but I'm almost sure it shouldn't be used. There is a bridge and lifts at the station but I don't know why these weren't being used.
Sounds absolutely fine as far as I can see-can't see any safety breaches there.
A member of staff with PTS was escorting people over a Barrow crossing. You don't always need a line block for that, if it's a fairly quiet stretch of line then the signaller may give permission to cross without actually blocking traffic, saying that there is one to pass in the 'up' and then nothing for the next 60mins for example. Station staff would then ring once clear of the track but I don't think there is any requirement for them to phone the signaller in full view of any passengers...
Infact what you describe sounds like common practice for delivering supplies to the station. As long as staff are present I see no safety breach by having non-PTS trained people on the line in such a controlled situation. Infact it seems a lot safer and more controlled than a train evacuation.