The situation where a contractor has been awarded two or more different contracts for different phases on the same site must be failry common because I have encountered it three times so far in my career.

It is a recipe for disaster for the Employer because if the contractor causes a delay on Contract 1 which then delays acces to Contract 2 then the same contractor is entitled to an extension of time on Contract 2 on the grounds of employer's denial of access.

There is no possibility in English law of the employer setting off his loss between seperate contracts.

He can only deduct LAD's from Contract 1.

Better to use the variation system on the first Contract to award new phases.