Thanks I had actually found a book and bought it hoping that it would help me despite it being for VS 2005 and thankfully it did.

This is the book:

http://www.amazon.com/gp/product/1590598547/ref=s9_psimh_gw_p14_d1_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=1V9E17C7MPDBS0QRD1KB&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

It explained to me that I needed to have the all the data needed for the master and for the detail in my dataset which I had not found anywhere else. It also showed me the type of code necessary to handle the subreport processing and I was able to adjust this to speed up the extremely slow subreport so that I actually filter the data appropriately on each subreport in code rather than loading the entire dataset for the subreport and letting the report filter it based on the filter set on the tablix.

Thanks for your help.