I would likely use a data merge on something like this simply to reduce the chance of error on my part when pricing changes. Put everything that does not change on master page(s). Use the regular page(s) for the variable data. Export out the variable data from Excel, LibreOffice, whatever, as a tab delimited file.
Depending on how much data, I would likely use three separate sheets, one for each of the restaurants. Then export the appropriate sheet for that particular restaurant. You would then simply swap out the data file for a restaurant as the data for that restaurant changes, re-run the merge. Export the new document merge to a PDF.
This is a classic use for Conditional Text...
Read about using Conditional Text in InDesign Help or by Google searching "InDesign conditional text tutorial". You can mark text like a price (or almost anything else, including anchored graphics) to be associated with a condition (Restaurant A, Restaurant B, Restaurant C). Then when you choose that condition, only price (or other text) appears or prints. Create PDFs of each of the three conditions for printing.
I would still use data merge for this...
But in my links I do have this one for using conditional text. The video at the bottom is a little plodding, but explains it fairly well.
Thanks very much for your speedy responces!
With regard to the data merge method I am not sure this would work for me because there is a lot of text and I need them to flow from page to page so would need all the text and prices in one text block (I hope I have understood your method correctly MW Design!). I have just had a look at the Conditional Text method and that seems as though it might work for me but one issue I might have is if one dish is removed form a menu all together then the text will run up from another block. I am sure there is a way once I have the master menu done to force the text to the next text block after the last dish I want on that page and then enlarge the text block a little to accommodate any movement of the dishes on that page, I will look into that!
Thanks very much for your help.
PS InDesign never ceases to amaze me!!
You can add a page break or a column break, as appropriate, wherever you need one, or simply adjust the size of the frame. Properly configured Keep options will help keep dishes from splitting, too.