You theoretically don't need to involve a professional but it would almost certainly be wisest to do so. The relevant form is among this lot. (It looks like it might well be TP1 but I'm not guaranteeing it!):
https://www.gov.uk/government/collections/land-registry-forms
If you take a look you'll see that you need to execute the transfer as a deed (Section 13) and that there's just a blank space provided to do so. (i.e. no guidance upon how to do it!). I reckon that I'm quite good at legal stuff but I certainly wouldn't attempt to get that form right without a bit of help from an expert!