(02 Jun 2016, 11:06 am)8222 wrote If I were you, I'd book NCL - KGX then hop it to STP and catch the Thameslink. One train straight from over the road and I swear it's cheaper than GatEx.
Or even try GC SUN-KGX. I regularly travel SUN - KGX and GC southbound are usually cheaper from my experience. Northbound can vary, but again, GC often are cheaper.