xeromist , you are 100% correct,
It is the USB sticks which are faulty.
Tried them on a laptop,
which gave the same results, 38MB/s
As a warning to other people, here is the
model of the USB Sticks
SanDisk
Ultra-Dual Drive
Go 64GB
for USB Type-C devices an A Connections.
Up To 150MB/S
Here is the link the them:
https://www.amazon.co.uk/SanDisk-Ultra-Drive-Type-C-devices/dp/B07YYK13LF/ref=sr_1_3?crid=1AH4MI76YV...I shall be returning them as "not advertised as such" !
Thank you, Happy New Year.........