I never spend much money on a LHR hotel...most I've paid was about £60 and that was for a 4* through Priceline.

If you can get the Premier for £39 then take it. As there are two of you don't bother with the Hoppa. Just get the hotel to order you a taxi with a set rate...shouldn't be any more than £15. The Yotel sounds ghastly for the price.