I want a belt like this that's secure but also that I can store credit card and money in a hidden secret pocket , any ideas?

You might have to go bespoke to get a belt like this wide enough to hold a credit card. There are plenty of belts, which will hold cash, but most are not of great quality. Try Barefoot Leather for the belt, they do good work, at a reasonable price.

I have a 27 inch waist, will this fit me please?

It will fit just fine, the system is very flexible and the belt itself is elasticated. The belt intermittently needs adjustment but will be easy to hide the end which is a nice & neat piece of detail. The quick release button also is a very useful touch.

Just to clarify, does it release with one push of a button, if it doesn’t how good is the lock and how do you unlock it? Thank you

Yes it does release with one push of the button. When putting on, you take off one side of the belt (both bits of buckle stay clicked together) then thread through belt holes with belt strap. Then strap goes through belt buckle. Good sturdy belt.