Jaguar S-Type Spark Plug Replace/Remove

Have Changed All But One Spark Plug The One Nearest The Bulkhead Cant Get The Coil Out No Room I Have Tried Twisting Left And Right But The...

Ever Since I Changed The Spark Plugs The Engine Has Lost Power And The Rpms Wont Go Past 3. Any Possible Problems?

Where Do I Locate,or What Discription Of The Area Do I Look For To Find The Spark Plugs/wires To Change Them Myself. Much Much Thanks