Thanks for your suggestion.
Cells are all set correctly. However, since the upgrade when computer set to Australian region it now says "British Pound (GBP)" not "British Pound (£)". Other regions do still seem to offer £ with A$ for Australian dollar.
In Numbers "Language & Region" option to change region was greyed out on my spreadsheet. I think that this was locked by choice of "System English" as language, changing this to English allowed me to change the region to UK. A slight improvement as £ is back but now has AU$ as prefix for Australian dollars which, to me, makes it marginally easier to see the actual figure.
Seems like a conscious decision by Apple to change the way currencies are displayed in Australian region, only Australian dollars can be preceded by currency symbol, every other currency only offers the three letter code for the currency. I am sure there is a reason for it but can't think of one!
For my purpose I don't really need to format cells as currency so I will probably leave spreadsheet set to Australian region and just change all the sterling fields to be normal decimal numbers with two decimal places. Leaving Australian dollars as currency will have those displayed with $ to show the differences. At the moment I have difficulty picking out the actual values when written as GBP123.45 rather than £123.45 or AU$123.45 rather than $123.45.
