Many thanks everyone.
The solution (s) is to adjust Kerning in the Character palette.
In my case the Kerning was set to Auto and making that 0 usually did the job. Additionally, I adjusted Kerning by 1-2 % and that also worked.
Usually, once I had made these adjustments and then reverted to Auto and 0s the text stayed correct, so a winner! For MSWord users there is another solution: Select text, go to Edit menu, select Paste and Match Formatting. That instantly replaces highlighted text which you then copy and paste into Publisher, all correct formatting and spacing! Just one proviso, if text is justified the justification does not happen so adjust in Word or when pasted into Publisher, which is easy.
And from the Publisher HELP menu (it was there all the time...!): To adjust kerning:
• With an insertion point made by clicking between two characters in your text, do one of the following:
◦ From the Character panel, choose a value from the Kerning setting, using the up and down arrows, the pop-up menu, or by typing in a new value. Auto will automatically kern characters by default. Positive values give expanded kerning, negative values give condensed kerning.
◦ From the Text menu's Spacing sub-menu, select one of the spacing options.