Average length of graduate studies in the UK in the life sciences What would be the usual time spent doing graduate studies (Masters + PhD; courses + research) in the UK for someone studying life sciences?

I am applying for a Junior Research Fellowship in hopes of doing a postdoc in the UK. However, one of the requirements is that I have fewer years of graduate studies behind me than I in fact have. I have other grounds to ask for an exception (pregnancy leave), but I am wondering whether my 2+4 years (Dutch) graduate program is longer than what the typical UK student does. I'm sure that programs vary, but if we were to pick a random UK life sciences postdoc, how many years would he have spent doing graduate studies?
Usually a master's course is 1 year and PhDs are 3 years. There are exceptions to this though, some mphil's being 2 years and some structured PhDs being 4 years. However, it is possible in the uk to go straight to a phd after undergrad. Therefore the number of years of graduate studies varies between 3 and 6, though the average is around 4 if you ignore the special cases.