Interesting, would like to see that if anyone has the magazine in question? Chances are it was an 86, although saying that electric freight wasn't a thing on the GEML then, as the NLL wasn't wired at that time. 85's did make it to Glossop/Hadfield testing the OHLE when it was converted IIRC, and right at the end of their lives someone on WNXX positively ID'd one on the blocks at St Pancras, so they did start to spread their wings before their withdrawal. Would love to know if 81's did the same.
Further to this, there's this shot of an 81 on the Garston-Dagenham on the WCML, and the caption makes for interesting reading as it suggests the 81's worked all the way through. There's got to be photo evidence out there of them on the Great Eastern/LTS, surely?
Link here: https://www.flickr.com/photos/actonwellsjunction/8566896057/in/photolist-81JzpW-81JzLb-8367w1-5LEg2R-81JCL1-8369Jd-81FtLe-83zxqq-o3YUnT-e42zJr