I've been in my role for just coming up 5 years. Due to the unusual nature of my role and who I work for within my organisation, I don't have performance reviews, my boss just signs off with HR each year and I get the standard pay increase and a small bonus every year.
I am aware that my role has grown and I am working my butt off constantly. About 3 years ago I asked to cut down to 4 days, as I have a chronic health condition that needs regular physio treatments and I just couldn't fit them in after work on a regular enough basis for it to be helpful. The reduction in hours was agreed and I accepted a pro-rata pay cut, as you would expect.
In the intervening 3 years, I have taken on more and more and I now work through my lunch hours and I start early and finish late at least two days a week, so I am now effectively doing nearly the same full time hours just over 4 days instead of 5 and way, way more work.
I've never really had anything much to do with HR, although we are a big company with an HR department, but I am raising it now.
I've updated my job description and sent it off to them and I reckon I am doing double the work I was originally taken on to do. Is there anything much they can do? Is it reasonable for me to renegotiate my pay? I'd really appreciate any input as I know nothing about this kind of stuff.