Problem solved. Found the information I needed on other forum posts here and also at this link: https://www.2manuals.com/product_info.php?cPath=107&products_id=1837
My wf3733 is now working better than ever. Admin / moderator, you can disregard, but I will leave this thread here incase someone else finds it in future.
with my wf3733, I pressed power button and spot on top right of screen (20 seconds) until the blue light by the power button flashed, as soon as it flashes, I let go of button and screen. It then goes into the mode to flash firmware (white text). if you keep holding buttons after light flashed, it will go into red text mode and you cannot flash.
I then used www.chiplesssolutions.com/download/FWF469TL_CL99J9_WF3720.zip firmware
and then the utility from https://www.2manuals.com/product_info.php?cPath=107&products_id=1837
everything working great, excellent value for the cost.