Hi dear members, need some advice please!

We are sending out a survey to our customers through Marketing Cloud system. (survey was itself created in SFMC)
Once a customer submits a survey, response gets recorded in SalesCloud Survey object 'Survey_Submission__c'. An auto Email then goes out to these customer from SalesCloud containing the same 'Survey URL' allowing them to change their responses if they wish to do so. 
Below is the Visualforce email template that we are using.

Issuse: How can i pass the customer name / Custome ID within this email template, so that if a customer clicks on the survey url, the system recognises the contact and makes the changes for that specific record in SalesCloud.


<messaging:emailTemplate subject="Survey Submission Email Notification : {!recipient.Firstname} {!recipient.Lastname}" recipientType="Contact" relatedToType="Survey_Submission__c">
<messaging:htmlEmailBody >

<img src= "https://companyname--uat--c.cs104.content.force.com/servlet/servlet.ImageServer?id=015200000HS2h&oid=00DN00008qOQ&lastMod=15827213900"/> <br/> <br/> <br/>

<p style="color:#2325C5">
Dear <b>{!recipient.Firstname} {!recipient.Lastname}</b>, <br/> <br/>

Congratulations, you have successfully submitted your survey
Please click on the below URL if you wish to change any of your survey responses.

<a href="https://www.survey_url_would_be_added_here.com/331578514d47s.pub.s.10.sfmc.content.com/i34gdhup?" > SURVEY_ID= "{!Survey_Submission__c.ContactId__c}" Change your submission here </a>

Regards, <br/>
Team XYZ
</p>
</messaging:htmlEmailBody>
</messaging:emailTemplate>

Kind regards!