Managed the 215 miles quite easily (except the a30 to being forced to walk up out of Penzance!
I assume you stayed on the A30 off the roundabout adjacent to the heliport?
This takes you onto a very steep uphill ( forming part of the ring road.) which I expect is the one where you used your 24" gear.( 12" = one foot: 24" = two foot )
Next time bear left at that r'bout taking you off the A30 & follow the signs to the Town Centre.Keep left as you pass the railway station & stay on the road along the flat sea front ( Wharf Road & New Road.) untill a roundabout ( IIRC it's the first one ) where turn right onto The Coombe.
This climbs gradually & easily upto the A30.Much easier & more pleasant than the ring road.
hth
chapeau your ride to LE