Thanks Erel,
I have recoded it with BMPs in an ImageList and it is much faster.
Credit needs to be mentioned here to Bob Chappell who seems to have written the original from 15/4/80 (or 14/5/80 depending on the version you have) as per npark.prg which can be downloaded from PET websites off the Internet (and then subsequently run on the VICE emulator). I have tried to contact Bob, but as yet to no avail. Bob, if you're out there, please get in touch!