Cannondale Synapse?
Specialized Allez Elite?
Any thoughts?
The Cannondale is regarded as a great, comfortable bike. I'd probably be inclined to go for that assuming a decent level of componentry.
Looks like Tiagra for a grand. I'm sure it was 105 when I went through the process last year though.
Exchange rates. Most bikes are produced overseas. I'd imagine a tiagra synapse at a grand is about right. Can always look to upgrade componentry as it wears to 105 etc. Espicially as the synapse is regarded as a top frame as is the Allez.

Check out the Reid Falcon Elite at Winstanleys it has a full 105 groupset for less than £549
A really good spec for the ££
https://www.winstanleysbikes.co.uk/product/80714/Reid_Falco_Elite_Bike
For better pics check the Tredz website.
http://www.tredz.co.uk/.Reid-Falco-Elite-2017-Road-Bike_87057.htm
Voucher will be with Hargroves Cycles.
]Can you persuade them to supplement the voucher with a bit of cash? http://www.hargrovescycles.co.uk/bikes/road-bikes/cube-attain-race-disc-2017-road-bike.html gets you proper hydraulics, rather than hybrids.
If not, I'd probably also consider http://www.hargrovescycles.co.uk/bikes/road-bikes/cube-attain-sl-2017-road-bike.html in addition to the Synapse and Allez (you might want to consider a cheaper version of the bikes with a lower spec groupset, if you want/need accessories).
If you buy a Specialized bike then you're paying a premium just for the name. At this end of the market where you're trying maximise bang for buck it seems silly paying 20% more for the words 'Specialized' down the tube. [unless the bike is reduced in a sale]
From what I've read, it seems that at this end of the market decent aluminium frames (Cannondale and Specialized) are better than cheap carbon. Although, I haven't ridden any carbon bikes to substantiate that claim.
