Use Tasker to swipe lock the screen for 10 mins then require password thereafter i'm looking for a way where i can use the power button to turn off the screen and activate the swipe lock. If the phone is left untouched/unswiped for 10 mins the password lock should come on.

There is one difference between this and similar posts i have seen, my Phone is encrypted so i cannot turn off the password as part of the method of doing this. 

At the moment the power button turns off the screen but can be unlocked at the push of any button which often results in unintended phone calls in my pocket, after a certain amount of time left untouched the password lock kicks in.

I've heard an app called Tasker can do something like this, will it also work with encrypted devices?

All i would need it to do is activate a swipe lock on pressing of the power button

Thanks
You are correct: an app called Tasker can do this. The feature you want to turn off/delay is called Keyguard: turning this off disables the password/PIN lock screen. So you could setup a task turning that off on the condition the screen is turned off, then wait 10 min, and re-activate it again.

Additionally, you might want to take a look at the Secure Settings addon for Tasker, which gives you some more fine-grained options towards this (and plenty of other benefits). Using this addon, you could e.g. have your device require the PIN/password unlock only once, and then not asking for it anymore (useful e.g. at home).