dd3 withholding poos - should we go back to nappies for holiday?

[Mummysgoneloopy]

Dd3 had been dry for a month - she was just under 3 when we toilet trained her - all went smoothly on the wee side of things, however she will not poo in the loo or potty & has started witholding her poos which makes for rather frequent skiddies & larger affairs in her knickers! Have tried rewards / star charts / & never make a fuss when it happens, but we go on holiday this Saturday - dh thinks we just take the pressure off & put her in pull ups (after all she will have to be in swim nappies anyway) - but just not sure...any ideas?