Use multiple URL arguments to prepopulate multiple entity reference fields I have multiple nodes of type 'schools'

I also have a contact form that i'd like to provide on a per school basis.

I.e. The user views a school page and can use an entityform embedded or linked to that particular schools page to generate a pdf letter to mail to the school. This letter will be pre-populated with the School name, School address, Head Mistress and other fields from the 'schools' content type that it came from.

I have set up 'entity reference' and 'entityreference prepopulate' as per this tutorial and have made some  headway.

However I can so far only successfully pass one item from the node to my form using url arguments ... how can I pass multiple arguments ~5-6 elegantly to prepopulate my entity form? 

I am open to alternative approaches, it would be nice to have the form embedded on the schools page...rather than linked (via the block in the above example)
You can follow the same approach given in the example.

You will need to rewrite the link from 

http://example.com/contactform?field_name=12345


to  

http://example.com/contactform?field_name=12345&amp;field_name_second=4567&amp;field_name_third=890


This should do the trick for you.

If you want it to look more elegant, then you can just pass the entity id of the referring object and then write some code to pre-populate the values based on the given entity.