IHTM14336 - Lifetime transfers: gifts with reservation (GWRs): the reservation: effect of consideration
Except in the case of land or chattels (IHTM14341), the fact that the donor gave full consideration for the benefit or enjoyment which they obtained will not be sufficient to say that there is no reservation.
Example
Alex, who is a partner, withdraws capital from his partnership capital account and gives it to Bella. Bella then lends the partnership an equivalent cash sum.
This is a reservation. Though Alex may pay Bella a commercial rate of interest for the loan, this payment will not prevent the loan being a reservation.