Welshman drinking French wine cold, as was Leonardo (2,5)
I believe the answer is:
Here is my best explanation:
'as was leonardo' is the definition.
(Leonardo Da Vinci)
'welshman drinking french wine cold' is the wordplay.
'welshman' becomes 'dai' (Welsh name).
'drinking' indicates putting letters inside.
'french wine' becomes 'vin' ('wine' in French).
'cold' becomes 'c' (eg on taps).
'dai' placed around 'vinc' is 'DA VINCI'.