All online sources point to Borthwick and over 1m3 of material. It may be worth a trip to inspect it all.
Have you seen this: https://archive.org/details/in.ernet.dli.2015.165833/page/n57/mode/1up
Several entries in the British Library Catalogue and in Kew’s National Archives so worth looking there if you’ve not already.
And lots of items listed on WorldCat.
And this item in York Archives: https://catalogue.exploreyork.org.uk/client/en_GB/default/search/detailnonmodal/ent:$002f$002fSD_ILS$002f0$002fSD_ILS:781724/one?qu=Cooke%2C+Troughton+and+Simms+Ltd.&dt=list&h=0
And this in the RAS Library: https://royast.cirqahosting.com/HeritageScripts/Hapi.dll/retrieve2?SetID=3548FC96-A89E-472D-B5C3-A99C93BF2149&searchterm=Troughton&Fields=%40&Media=&SearchPrecision=20&SortOrder=0&Offset=3&Direction=%2E&Dispfmt=F&Dispfmt_b=B27&Dispfmt_f=F00&DataSetName=LIVEDATA
Good luck finding what you are after.