Thank you so much for the detailed response!
Just to clarify - you said that a second charge would be preferable to a Declaration of Trust - but I don't completely understand why this is the case. Is the second charge more official? Because it sounds like both options give my parents the same rights.
Is there no way to make my parents legal co-owners of the property and add them to the title?
Also, would we encounter more difficulties if we wanted to remortgage with a second charge or a Declaration of Trust, or is there no difference?