After much cogitating, I ended up doing a complete 180 and I have decided to go with a Whyte Portobello. I managed to get a 2018 version for an absolute steal (not literally) and pick it up tomorrow.
I have just ordered a couple of 32c Gatorskins which I'll thrown on straightaway as the only apparent criticism of the bike is the stock tyres.
I am really looking forward to getting it. Despite initially wanting a roadie when I sat and actually thought about the kinds of riding I do I feel that the Whyte will be absolutely ideal for me as it will be quick enough for fitness stuff and versatile enough to do anything else I am likely to do.
Thanks to everyone who contributed and to Vickster for her advice about the brand. I have only ever heard good things about them.