The provider will instruct a surveyor to give a professional valuation of your property that would define the amount that could be released. How much can be released is also dependent on your age and that of your partner (if you are making a joint application) and the value of your property.
Timescales will vary from provider to provider. However, it usually takes up to 8 weeks from the day your application is received by the provider to the day your money is received by your solicitor.