Encore/Applaws is potato - as is Arden Grange sensitive but I don't know any shops that sell Arden Grange - My friend buys it somewhere but it may be a garden centre.
btw - the Encore/Applaws is going down really well here. Willow is off her food ATM and that is the only thing she is eating.
Ingredients from pack
dry chicken meat, dry potato, fresh chicken, poultry oil, poultry gravy, beet pulp, dry whole eggs, brewers dried yeast, salmon oil, cellulose plant fibre, cranberry extract, yucca extract, citrus extract, rosemary oil exract.
I am assuming the cranberry extract is d-mannose.
btw - I just checked a purina one bag and it has maize and soya as well as rice in it.