Dynamic Year to Date Calculation

I have attached a small example of my SS and where I have got to so far.

I want to produce a YTD calculation that rolls on as the month of the year progresses.
I have a large data worksheet that is analysed by year by Pivottables into seperate worksheets.
I then compare these yearly figures in another SS.

So for example I end up with a revenue table which is Month by Year and it is this I want to obtain the YTD values from.
One complication is that our year is April to March.

I have made a start which is in the attached. It kind of works but seems very clumsy.
Can anyone suggest a more elegant way of doing it?

Thanks

Thanks for your reply.
That use of SUM(OFFSET... is new to me, I am trying to work it out!
How does it step to the next cell to SUM it ??

I have also noticed that copying my table and formulae into a blank SS for posting was not accurate. So I have attached a corrected one.

I have used SUM OFFSET as suggested and produced a relatively simple formulae which provides a dynamic YTD figure.
It is slightly complicated by the fact our year is April to March but otherwise is straight forward.
The working version is attached.

Cheers