Thanks for the help. I deleted all the folders and started a fresh. I did the following....
1. Install the Mame Compiler to D:\MinGW\mingw64-w64
2. Unzip the Mame Source to D:\Mamesrc
3. Unzip the 'compile_extras.zip' onto D:\Mamesrc
4. Edit MakeMAME.bat and PatchMAME.bat from the 'compile_extras,zip' so the drive location is correct (D:\)
5. Copy all the .diff files to D:\Mamesrc
6. I then double click the cmd.bat file from the 'compile_extras.zip' which loads command prompt with admin right in D:\Mamesrc directory
7. Type 'patchmame' and patched in this order:
148u1.diff
148u2.diff
hi_148.diff
0148u2_groovymame_014a.diff
cavesh3_148u2.diff
all patched fine and the typed 'makemame' which gave me a mame64.exe file after 15 minutes, so all appears to be good!

Have a question about using GroovyUME, is this compiled into what i have done above as i have never tried using the UME section of GM before, how do i load a NES rom for example?