Hi Andy,

I know damn well what you mean about an SD card playing up. The problem with the D4S is that the card slot is stupidly placed so I tried several things. You also have to appreciate that there is a gap behind the card slot, so the card can easily fall into the machine and get lost in the electronics compartment.

First attempted solution :- Fill the gap with a printed fillet. - Result - fewer lost cards, but more awkward to insert and take out card.
Second attempted solution :- SD card extender, good idea but failed very quickly, resulting in card misreads.
Third attempted solution:- Cut away the machine enclosure to get access to the card.Click image for larger version. 

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Fourth (successful) solution:- WiFi Card. It works well enough to stick with it and no major change to machine.

Cheers,

Rob-T