yep - Enervite is a definate.
Have you tried
Complan and
Complan with Oats? It's a build up drink, has everything in it and all you do is add water or soya milk (my lot only like the 'original' flavour). I offer the complan with oats warm or cold and it's always been a favourite.
You can get them in Superdrug, Boots and most pharmacies.
Beth