My advice would be to:
1. check that you have a screw-in chimney extension to ensure that the products of combustion are carried above the level of the pop top vents,
2. remove the front cover and clean out all dust from the inside and from the fan blades. You will be amazed what muck accumulates in there and it really stinks when it gets hot. You may find this post useful.
3. check that the igniter battery is good and replace with a Duracell PP9 or similar if in any doubt,
4. Make sure that the gas supply is turned on (there is an isolating tap for the fire - one of three - under the sink) and then try lighting the heater to make sure all is working fine before you set off on your trip.,
5. Consider taking a small oil-filled electric heater with you if you want to leave the heating on all night (some people are worried about sleeping with the gas fire on - a carbon monoxide alarm is a good investment).