Hi Dave... no, you can't produce a profit and loss between any two dates. I am planning to overhaul the filters to make them more flexible and easier to use (for example, using 'date picker' fields like those already used to specify Statement date ranges).
In the meantime, if you really need the figures between those two dates, a workaround would be to produce two profit and loss reports: the first starting on 29th July, which will include all of April's figures, then another ending on 5th April, which will give you the correct figures just for the part of April you're interested in. If you export these reports, you could then combine the two in a spreadsheet program.
If you want me to do this for you, let me know...