Slug creation code

I have a plugin made which uses a page with a GET value. This accesses a database and takes information from a database, but it also needs to provide links to other pages which have been created with wordpress, using the same values.

Getting the information works fine, but if I use a link for a place which has any html entities in it, such as “Melmerby & Locherby” then the links fail, obviously because the slugs have hyphens instead.
Is there any way to create these slugs, as all the pages will be using the wp default ones, so just the generric code would work.

Alternatively, is there a way to get a permalink according to a pagename with a specific parent, as that would work just as well.

Cheers