So there is an issue with the latest version of Retroarch. It seems that 1.4.1 and the latest mame core crashes regardless on direct load in Retroarch. Normal roms work fine (though some crash randomly) but loading CHD software list content such as CD-i, NeoGeo CD etc now crashes upon loading the content.
I tested going back to my old RA build which I used before updating to 1.4.1 and that setup works (CD-i chd, dummy file and bios in appropriate folder).
So I can only assume it is not the actual core but actually Retroarch that crashes considering it works on older builds.