Aluminium Road bike frame with 30mm tyre clearance - without gimics

Kinesis T

Size 54cm/Medium.

Shimano 105 with Ultegra level brakes....

Nice and cheap, of course.

I have a whole bike like that available.  Kinesis T.  Aluminium, fit 30-32mm clearance (28mm with guards) without guards.  Has mounts for guards and rack if req.  It is the precurser to the Kinesis T2/3.  Light aluminium frameset and takes rim brakes etc.

Let me know if you are interested.  It's fitted with shimano 105 kit  but the brakes are Ultegra level.

With disc brakes now pretty ubiquitous and wider tyres becoming more normalised, most endurance road bikes (and even some more racey bikes) have clearance for 30mm+ tyres, so you have plenty of choice. You could go for anything from the bargain bucket Triban RC 100 (~£300) up to the luxurious Mason Definition (>£3,000).

You might need to narrow it down - budget? Intended use? Other must haves/must not haves? 

Tifosi Rostra? They are sometimes badged as a gravel frame, but the tyre clearance isn't up there with serious gravel bikes but 38mm would surpass your requirements

Currently £379 at Merlin

Have a look at Kinesis. Built with UK roads in mind, all current models have the clearance you need.

R2 - all rounder

RTD - race bike

Some are available as full builds If you want something even more versatile then they have a range of gravel bikes too - G2, Tripster, and GX Race.

You can get a Genesis CDA for £650 at the moment.

Will take up to 40mm tyres IIRC. Comes with 35s.

I've got got a CdF which is steel but otherwise very similar. It's a great bike.

If you're quick and either quite tall or not very tall at all, consider a Dolan Preffisio, available for £150 as a run out special. Takes 28 mm tyres with mudguards so can probably do 30 mm without. A friend of mine has one and likes it very much. Lovely paint as well.