Thanks for the replay, I am aware of that option, but the thought of having to prepare a whole load of pngs, is not desirable, especially as the goal for this game is to have it available in at least 3 languages one of which will use cyrillic script - So it;s essential I can pass the text through.
The solution to the problem is to have a variable background image which is triggered by the number of responses. Getting the graphic the correct size is fiddly as with elements in the response box you don't have the same level of dynamic control - but we will get there