If you have administrative access to a repository, you can prevent users from committing generated files by recognizing their filename extensions.
Go to any folder in your repository, one under the address https://scc-forge.lancaster.ac.uk/svn-repos/, and follow the Hook scripts link. You'll see a table listing new and existing scripts for that repository. Pick the Add entry Forbid suffixes.
Submit your selection to make an entry appear in the upper part of the table. In the field, enter the list of forbidden suffixes, space-separated. Activate the script, and submit again.