I'm just need to pass a URL parameter to a form and preselect a dropdown field.

General information for the website: The website is for an event management company
Kind of development: Customization of existing website
Num. of web pages/modules: 1
Description of every page/module: Simple order page needs to accept a string from the URL and then preselect a dropdown menu.

In practical terms, the user clicks one of 3 price options on a previous page, and are brought to the order form. I simply want that specific price to be preselected.
Description of requirements/features: These are the two pages in question. On the first the user selects a page, and the next, the form should display the correct price.

Select page : http://www.icongroupltd.com/register-test/

From page : http://www.icongroupltd.com/register-now/?defaultvalue=
Extra notes: I've already spent some time implementing these steps http://www.featheredowl.com/contact-form-7-default-select-value-url-query-variable/, but the value I'm trying to pass contains spaces, periods and commas which break the function. So what I need is you to work around this so that the following prices can be displayed in the dropdown box on the form page, once the use has clicked a box on the previous page.

Super Early Bird (1x Delegate) £999.00
Super Early Bird Plus (2x Delegates) £1,499.00
Special 3 (3x Delegates) £2,299.00