MEng over 4 years with a placement year included?
It should be 4 years for the MEng by itself.
Do you have a link to those pages? Perhaps they include the placement as an optional extra instead of labelling it on the course page. I would suspect it be 5 years for MEng + placement though. I started a BEng and in the first week they told us that we'd be put down by default as full time students on a sandwich course, so the option to do a placement was still open... It just wasn't advertised as "BEng Engineering with year in industry" on the website.