Investment trust HSBC Infrastructure is making good on its pledge to carry on buying, and has boosted its stake in the Greater Manchester Police Authority public finance initiative project.The trust, which specialises in investing in infrastructure projects, has upped its stake in the project from 50% to 72.92%. Financial details of the deal were not divulged, other than to say that the deal was one of the three bolt-on police project acquisitions for £8m mentioned in its interim results announcement earlier in November.The other two projects, the Metropolitan Police Training Facilities and the Durham & Cleveland Firearms Training, have already been completed.