I agree that it is poorly written, but it reads as if..
First bid = Rejected out of hand.
Second bid = £1.2M+SISU keep Ryton+bonuses (up to £10M).
Third bid = £2M cash+SISU keep Ryton+bonuses (up to £20M).
Fourth bid= £7M cash+bonuses (could exceed £20M) and Consortium keeps Ryton.
The bonus...