Hi Ollie Cadman-Kerr,
Thank you for reaching out Microsoft Community and posting your concern regarding your Surface Pro 7 camera lens. If you see the dirt from the inside, we don't recommend cleaning it out. Kindly contact our live support team and check options for your device, you may reach them through the numbers listed in Global Customer Service phone numbers (microsoft.com) under For Business users. This also works with Home users , just select Surface then Home as a type of user in the IVR prompt. You may also reach them through this page: Contact - Microsoft Support.
We hope this helps you out. Otherwise, don't hesitate to respond to this thread if there’s anything else that needs to be addressed.
Kind regards,
Lavenia