Ok so I have a Tomtom live 750.Ive patched the navcore, and put the latest uk ROI map on. Used fast activate to get the dct and all good. Its activated on the unit.
It also came with a 4gb sdhc card with Europe on which I didn't want. So I formatted the card in FAT32, I did this by connecting the tomtom to the pc.I see both the internal drive and the SD card.
I put the map on I wanted onto the sd card ( there is a meta for it ) as well as the meta file.

I run fast activate and it only sees the tomtom internal drive.
Pc sees both drives and I can access both.
Unplug the tomtom and using 'switch map' on the unit it also shows the map on the SD card, (yes I know its not activated, I just wanted to see if the tomtom was reading the sd card -It must be to see the map)

So I've tried a soft reset - hoping to get the tomtom to format the drive.. I formatted the card in fat 32, then put it in the tomtom hoping a soft reset would ask me to format the card -- no luck. Its not asked me to format it yet.
So tomtom sees the card, pc sees the card but fast activate only sees the internal hdd on the unit. I tried typing in the drive letter of the sd card and still no joy..

I'm now at a loss on this.
Any ideas please ?

Sorted it... and i may now help someone else out .

To activate a map on your memory card(SD) and not the tomtom internal memory

copy fast activate to the map folder that youre trying to activate.
Also copy over the tt.BIF file from internal tomtom memory, and paste the copy into the SD card Root.
you want to activate.
Then run it.

you don't need the sd card.
put uk ROI map in root from tomtom,
also put winrar activate there and unzip.
run administrator then.
maybe you have to turn off your comp security first.
do the first 3 lines from activate and finish.
go back to tomtom,
disconnect it from your comp and it will update it.

check meta and updated meta of uk ROI is there ?

please read first line again.
I've already put ukroi on unit and activated it fine.
The problem was getting fast activate to see the sd card.

You appear to have resolved the issue, but so that others understand the correct procedure ..

To activate an additional map that is on a new SD card, make sure that there is also a copy of ttgo.bif (copied from the internal memory) on the card (in the root directory) and that you have the LATEST FastActivate ALSO in the root of the card. Then run the FastActivate from the card.

Reading the tutorials available on the forum will avoid making elementary mistakes.