Thanks again for your reply.
Following your BMP085 suggestion, I checked the circuit and found a dodgy connection of SCL into the Proto-screwshield. I am now getting outputs on both monitor and LCD. I now just need to format them properly. 
BMP085 Barometric Pressure Sensor Quickstart - SparkFun Electronics - This is the source of connection and code for BMP085.
My apologies for wasting time!