After you have signed a contract, you have ten working days to have it checked over by your solicitor, then you go unconditional. If you are buying “off the plan” then you will not pay for it until the section you are buying has officially been given a separate title. Then you have 5 working days to pay the balance of the balance of 90%. You will have plenty of notice in the run up to titles.
If you are buying an existing section which already has title, you will need to pay the deposit once your solicitor has approved the contract and within 7 working days settle in full, this can be extended by arrangement.