Get the aero kit, crawl, walk run is nonsense, it is the slower cyclists who benefit most from the aero kit, faster cyclists only make minimal gains from aero kit. Also I have had some experience with the Specialised Allez, it is a good bike and it is adequate for racing triathlon, however it has quite "slack geometry and set up" - this means it errs on the side of comfort and not speed. If you really want to go faster on the bike get a more aggressive and stiffer frame (in the correct size) it will make a difference, and yes it will cost you money. Try Cannondale CaaD 9 at 800 quid for tiagra equipped bike as a starting point ... then work up. Good luck, also test ride other bikes on your circuit.