What do you mean 'what's to discuss'? Investment is good if it will benefit the whole of the UK if they are using this amount of money where are the assurances?
This article from last year shows the commercial interests are not passenger travel.
'It looked closely at how an operator of the UK-conceived vehicle might meet the demands of its market.
Those requirements would be primarily to loft big telecoms satellites high above the equator of the Earth, but also to put smaller, Earth-observing spacecraft in Sun-synchronous orbits (a type of orbit around the poles). These are the sorts of jobs the Ariane 5 rocket does today, and which Ariane 6, currently under discussion among European governments, may do from the early 2020s onwards.
Skylon is not in that discussion space at the moment - but it may get there at some point in the future if further technical studies prove positive and the financing can be found to push the concept forward.
The Skylon-based European Launch Service Operator (S-ELSO) study examined some of the hardware the vehicle would need to place satellites in orbit, and aspects of the economic model that would allow the operator to turn a profit. It even looked at how the vehicle could work out of Kourou in French Guiana - Europe's spaceport.'
http://www.bbc.co.uk/news/science-environment-27591432