The TSEM does give some examples of what HMRC consider a bare trust and what they don’t. Interestingly they have an example where access for the beneficiary is only available from age 21 and this, in their eyes, is a bare trust, although the example is on death rather than lifetime gifting.
https://www.gov.uk/hmrc-internal-manuals/trusts-settlements-and-estates-manual/tsem1563
Regards
Neil Jones
Canada Life