What Bike to Choose

Dont ride an expensive bike too and from university.  It will be stolen in seconds.  Only use said bike for training rides where you leave and arrive at your digs.  Even then, uni digs arent big rooms with space for bikes.  That means your £3k bike left in public view, it will be damaged or stolen.  

Use a cheap steel framed bike, train hard and use it with a very good lock.  Replace the QR with bolt thru axle like Halo https://www.tredz.co.uk/.Halo-Hex-Key-Skewers_29491.htm?sku=64304&utm_so...

Remove all lights after each trip.  Make your bike the most undesirable to be stolen

You are a student, and suggest, not unreasonably, that your budget over the next few years might be tight. My advice would be to take a look at 2018 leftover stock, at the spec you are looking for, from a range of manufacturers. Typically 2018 models will be discounted by around 25-30% by now, and an independent might even be open to a bit of further hard negotiation. New bikes are a buyers market. Take your choice of either getting a better spec bike for the same budget, or getting your target spec with money left over for the beer fund. 

I don't know why you're specifically choosing between two flavours of the same Trek bike or what level rider you are, and I'd echo the recommendation to only ever leave it locked in your room, but even so I'd give serious consideration to a slightly cheaper option. Something like a Cannondale Supersix with Ultegra and discs is only £2k and under 8kg depending on wheels - yes, slightly heavier, but a hugely well regarded bike and only £1800 at Pauls Cycles (for example, no connection).

Mate, I cannot advise you on your glorious choices, just get the one you love most.

I can however offer a bit of knowledge on keeping her.  Unfortunately universities are are hotbeds of bicycle theivery.  So be very careful.  You might want to have something tough, second hand and for a couple of hundred quid, just for easier getting about.  Very good locks, and use them well.  Young people have not always learned much about security and the local scrotes know this.  Your housemates will not care about your bike as much as you do.  Get proper insurance and follow it's many clauses, you don't want to pay the money and get nothing if you lose your beloved bicycle.  And it's difficult, but let her get dirty, clean the drivetrain of course, filthy bikes do not look as good, and there will be a lot of shiny, badly locked bikes around, for a while at least.