BJT in saturation mode equations
Help really appreciated

I'm going to trust you on that point Miss Mulan.
Your circuit won't be behaving like an active (and saturated) BJT any more - there is too much forward bias between base and collector for this to happen and, all rules about transistor amplification are laid-to-rest and, the BJT behaves like two forward biased diodes: -

Compare voltages and currents side-by-side and you'll see that they are virtually identical. The main point to note is this: -

the collector current is flowing from the collector to the 1 volt
power supply rail via the 100 Ω collector resistor.

That means all bets are off when trying to analyse this circuit as a bona fide BJT problem because collector current is flowing the wrong way.
BTW the diodes simulated above are 1N4148 devices. So analyse it as two diodes instead of a regular transistor.