Hello Kevin,
Thanks for being in touch.
I take it you want to renew the current number plate, rather than take it off and put it back on again.
No screws = stuck on, and they do stick well!
To get them off entails the use of a hair dryer and carefully pulling (not levering). Getting the remnants of the patches off? Take it as not worth the effort - just reposition the new patches so they don’t overlap the old.
Kind regards,
Gareth.