You'll be cutting it a bit fine, 45 mis from landing to Hetherington House. Its a bit of a trek, and you would want to arive at the interveiw fresh and awake. So I recomend you book yourself into a hotel the night before, probably be a bit more money then your wanting to spend, but arriving at the interview not streesed or rushed will make you feel more confident, and you need to 'invest' in your carreer. Try the Jurys Inn Heathrow rates start from £80 I think and its just up the road from Hethering ton House. St Giles Hotel in Feltham may be cheeper. All the Best. Its a great airline to work for.