The best substitute for Wingel in the current Winsor & Newton range is Liquin Light Gel.
Now discontinued, Wingel was a little difficult to break down and mix smoothly with colours. For this reason, Liquin Light Gel has been developed with only a slight structure by comparison.
If a little more structure in mixes is required, add a little Liquin Impasto medium to achieve the Wingel consistency. This should be done with care, as it is not as transparent as Wingel or Liquin Light Gel.