Thanks everyone for your help. It's greatly appreciated.

The clause to "release the deposit" does sound like the vendor is in need of cash to buy her property. But at the same time, it appears like the vendor has yet found her deal, by including the following clauses:

Completion date: 18 weeks, subject to the following special condition:

"Notwithstanding any other provisions of this Contract, the Vendor can require the Purchaser to settle earlier than 18 weeks from the date of this Contract by giving the Purchaser not less than 28 days Notice. However, the Purchaser will not be required to settle any earlier than 42 days from the date of this Contract".

Any particular strategy you could suggest in this case?
Many thanks.