Is it wise to take P7 after two and half year break and sit for exam without going for class

Hi,

yes it is possible. However, P7 will be harder now as you are required to have the accounting standard knowledge of P2 not as it was F7.

You should get the most current books and see how you go and if needed look for good tuition. Try working with any study groups on Open Tuition, you will find yourself looking in to areas you may have overlooked otherwise.
If needed the cheapest class room (online) would probably be LSBF, the tutor is I’m told very good.

Good Luck