Trouble is you don't want any more of that gigantic GW Series 1 kit installed anywhere else.
Windermere isn't going to host 140mph multiple-pantograph trains anytime soon.
The same low-profile kit as used at Oxenholme for the northern WCML in 1974 will do fine, or that used on the Paisley Canal branch in Scotland.
UK Master Series would be my likely bet - that covers the best of Series 1 & Series 2 (mainly S2) along with various Mk3, UK1 (from WCRM), GEFF (Great Eastern Furrer+Frey) and SICAT (Siemens Catenary; as used on the Larkhall branch) assemblies.
Most structures on the WCML were 152x152 UC steel sections, now largely out of favour for higher speeds and higher, independent tensioning arrangements (12kN/15kN for modern equipment); the UKMS range certainly doesn't specify them as standard sections anymore.
203x203 UC sections are now the smallest sections, and are used on most single track structures. I believe they'll most likely form the majority of structures on the Lakes Line if it *officially* goes ahead. With its lower speed, I wouldn't be surprised if they go for a lower tension value in the C&C too (11kN in each).
