Peel don't spend their own money, the land was virtually given to them when they took over the Mersey Docks and Harbour Board/Company.
The pre-development costs are often provided by council and various grants. They are renowned for raking money out of councils then doing virtually nothing or worse still the Council have spent so much money that there is no return and Peel start making demands or different plans that the Council daren't turn down. Peel and Salford Council are at near permanent war after tactics that appeared that way.
As with most developers/builders, they don't build until they have firm buyers or leasers unless its a certain profit maker.
It amazes me that firms that operate heavy tax avoidance are allowed to be given grants, they rake the money in both ways.HERE
is one of many articles on them.