Resourcing rail replacement buses - why does it vary so widely by TOC?

[Bovverboy]

First Group is also thought to be very keen to go for the cheapest quotes, regardless of quality.

The rail replacement bus operating the replacement for the 2309 service Manchester Victoria to Liverpool Lime Street (which operates a minimum of eight nights out of forty-two, and which has a nominal journey time of up to 2 hours 32 minutes), has recently been mainly exactly that - i.e. a rail replacement bus, rather than a coach, which is what had prevailed previously.