I'd go with this and Stanley knife it to your Heart's content.
https://www.screwfix.com/p/floplast-drain-guard-black-305mm/78832?tc=IA1&ds_kid=92700055281954505&ds_rl=1249404&gclid=CjwKCAjw7IeUBhBbEiwADhiEMcata5NHKmtRRC4lMW-YkXRiZA4wz_l_IKP5ocYPBYwW6qNYtS3KZxoCykAQAvD_BwE&gclsrc=aw.ds
I've got one of these and they're not up to being stood on. They'll handle being accidentally kicked but they're pretty flexy.
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I'd go with this and Stanley knife it to your Heart's content.
https://www.screwfix.com/p/floplast-drain-guard-black-305mm/78832?tc=IA1&ds_kid=92700055281954505&ds_rl=1249404&gclid=CjwKCAjw7IeUBhBbEiwADhiEMcata5NHKmtRRC4lMW-YkXRiZA4wz_l_IKP5ocYPBYwW6qNYtS3KZxoCykAQAvD_BwE&gclsrc=aw.ds