Thank you sergio2 for your reply.

I see, I've been using my memory-map map and exporting the image as a bmp file.
Then I used a MAPC2MAPC to create my kmz file.
Looking at my kmz on GoogleEarth and counting the tiles, they were as you said over a 100.

Just played around and worked out that as long as the bmp has an Easting of about 20km and a Northings of about 6-7km, I get just under a 100 tiles!

Just got to find a program now where I can make an img file from a bmp file?
Would this give me a greater area coverage?
Also would I loose some map quality if I could create a img file compared to the limited tile size of kmz file?

Thanks for any thoughts on these questions