Well it turns out my original problem of roms failing to transfer over the network to the sd card may actually be caused by either a faulty sd card ao a fake!
I have tried to start from scratch and after cleaning the SanDisk 128gb sd card with sd formatter the card now only shows it has half the capacity as it should do, I've tried writing recalbox to the sd card which it does but really slow, I've then tried copying a file directly to my sd card whilst its plugged into my laptop and it only has a transfer speed of 1mb.
I got out my old trusty samsung 32gb sd card, replicated the above that I tried with the new card and transfer speed was around 30mb. Wow thats a massive difference.
So put the old card into my pi, tried transferring a few cd based roms and it worked absolutely fine.
So this thread is now solved as it is a sd card fault.
Thanks all