$5M of that $8.5M is already allocated and we don't even know if...

$5M of that $8.5M is already allocated and we don't even know if that includes the $1.75M for Derby so no, they effectively have $3.5M cash and maybe half that if the $5M doesn't include Derby. They also have their share of US$118M+ $13.5M in brand new debt that "Octanex N.L. has provided a proportionate corporate guarantee and undertaking in respect of the facilities".
So I think $3.5M and a ton of debt is a valid observation. It's not a value judgement on OXX as a company, the debt is fine given the project, it was just a judgement on how much cash they have spare to be taking Derby forward. I think it's unlikely. Then again maybe OBL do turn around and do another firesale to them of another 25% of Derby (assuming they gain full control) -valuing their remaining 50% at $3.5M wouldn't that be great?