I confess that I am still a serious beginner with spiders.
I worked my way through the key to Linyphiidae (https://araneae.unibe.ch/genkey/25/Linyphiidae ) at araneae.unibe.ch and can see I went wrong in my estimate of the position of the Tm1 trichobothrium. I think that was because I included the length of the joint with the tibia as part of the metatarsus length, which led me down the other branch from couplet 8. That led me to T. affinis.
I also tried the matrix key (https://araneae.unibe.ch/matrixlinkey ) on the same site, but my prosoma measurement of 1.1 mm excluded G. dentatum and I ended up with a set from which T. affinis was also the only choice that looked plausible.
I was not satisfied that the epigyne matched T. affinis (although it looked closer than many other species), but I did not see any plausible species that I thought matched better at https://arachno.piwigo.com/index?/category/455-linyphiidae . I think that in my scan of this page, I was mentally focussed too much on the blackish curved margins at the posterior end in my photos of the epigyne. I can now see that G. dentatum is indeed a good match.
I was unsure whether the problem was my rank inexperience at interpreting spider genitalia or that I was way off the mark.
Thanks again for all the help. Off to correct my errors.
I'm living in Denmark and was just visiting my childhood natural history haunts for a few days earlier in the month (https://www.inaturalist.org/observations?user_id=dhobern&on=2017-11-05 )
Very best wishes,