I took screenshots and animated the render myself in aseprite. I chose 500ms as the length of the frames as the flicker looked relatively accurate to me. If this is not optimal feel free to either vote on the download or replace my render with a more accurate one

EDIT: I changed the render to have the same flicker rate as the export from zxnet.co.uk (6 frames of 160 ms). This made it out of sync with the Qteletext editor preview however, so I don't know which one is more accurate