Granted Aldi are a lot better than some people make them out to be, but when it boils down to it I think the majority of people (including Kirkland who know doubt are trying to attract a more prestigious supermarket name than Aldi) would say they are not regarded as a high quality food retailer. I don't think Aldi would be seen as a major anchor store for Marple nor would they attract enough people into the town which Kirkland have made out they are looking to get in their leaflet. I think given that Romiley has an Aldi, the way the development looks. i.e. its not a box standard off the self retail unit, the presentation of the leaflet with green banners and its text font, it just doesn't come across as an Aldi.
My thoughts are that Kirkland are in discussions with either Waitrose or M&S Simply Food. Both are more plausible than Aldi but to be left field and add yet another supermarket to the mix of discussion what about a Booths? They are a North West company, they are very selective in the whereabouts of their stores, have a good selection of local produced goods, invest in attractive buildings and employ people who are really knowledgeable and passionate about food. I know they are seen to be expensive and the Waitrose of the North but I think they would be a good fit for Marple.