Get ready, this is a technical one!
The following link is to Bosch's website, where you can access line drawings for your specific Bosch cooker hood.
First click the 'United Kingdom' link. On the next page you have to type your model number in the 'E-number' field of 'Appliance search', located on the right hand side of the page. This should then bring up the line drawings for your cooker hood and instruct you how to fit your locks.
P.S. If you are having trouble locating the model number on your cooker, check our guide to locating model numbers here: http://www.espares.co.uk/findingmodelnumbers.aspx#a1