How difficult is is to change my 1997 1.4 Astra Engine?

My Cam belt went on Monday and there is damage to the head. I have sourced both a recon C14NZ and a second hand compression tested replacement engine for £400 and £175 respectively. Before I embark upon the task I wondered if anyone could advise me as to how much time it would take and whether any specialist tools and test equipment would be required.