£100m seems a fairly decent offer to me - the government only spent £1 on the airport, so if you write off £40m of debt, that's still a £60m profit. £200m of further investment would certainly be welcome too, and help modernise the airport
Given that its a space related company interested, it will also help cement PIKs place as a space launch facility. It will give Orbital Access a real incentive to operate in Scotland, and will bring considerable benefits to the local area. Without that incentive, they may well end up moving down to Newquay, which seems to be attracting a lot of government funding at the moment to attract space launch companies.
Sounds like an all round good deal to me... there must be a hell of a deal on the table if they're not considering it?