There is no one answer for everybody. It depends on your personal situation, the property and your plans for it. A minimum value of £75,000-£100,000 is required by many lenders and you can get up to 75% of the value of the property.
If you can provide additional property as security 100% is possible.
Searchlight Finance Limited is registered in England and Wales No.07929050 Searchlight Finance Limited is authorised and regulated by the Financial Conduct Authority and is entered on the Financial Services Register (http://www.fca.org.uk/register) under reference 743220. The FCA do not regulate Business Buy to Let Mortgages or most Commercial Mortgages and Bridging Finance. ICO Number Z3109319. Your property may be repossessed if you do not keep up repayments on a mortgage or any debt secured on it.