Which bike dilemma

I'm looking to replace my old Carrera Zelos with a proper road bike, now that I've decided I enjoy cycling (social and the odd sportive, maybe a long charity ride). At the moment, I am stuck on two options and both are appealing.

My first choice is the Felt Z75. The 2015 model features a full 105 11-speed groupset on an aluminium frame. I have ridden the bike and it is really comfortable and I love the look of it. I can get it for around £790 online.

My second choice is the Felt Z6. The 2014 is on sale with wiggle for £780. It's features a carbon frame with similar geometry to the Z75. The groupset is mostly Tiagra 10-speed with FSA bottom bracket and chain set. The frame seems to be consistent through the Z-series, so at this price point I am still getting a frame that is used in the higher spec'ed bikes.

My dilemma is : Do I go for the better groupset on the aluminium frame or do I go for the lower groupset with the carbon frame? With the carbon frame, I have an upgrade path with the groupset and can replace components with 105 as the fitted one's wear out. Both bikes would benefit from new wheels, but the aluminium framed Z75 doesn't leave much room for upgrades going forward, unless I replaced the groupset.

At the level I ride, I doubt I will notice the difference between shifters on either bike. Weight wise, they are pretty similar and the matt carbon finish is just as appealing as the finish on the aluminium frame.

At a price difference of £10, there is not much in it. Thoughts are welcome.