Beetle galleries found on dead Wych Elm in small wood.
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These can often be separated by size. If the central vertical egg gallery and radiating larval galleries are 2-6cm long, it's S. multistriatus, if larger (to 10 and 15cm respectively), it's S. scolytus.
The two species of Scolytus using elm construct vertical, one-armed mother galleries. Normally S. scolytus attacks the tree trunk whereas S, multistriatus uses the small branches. The mother galleries on your photograph are two-armed and horizontal typical of the large ash bark beetle. Look at the bark on your second photograph and I am sure this is ash bark not elm bark.
I agree this is Ash bark beetle - I think the latest revisied name for this is Hylesinus varius (formly Leperisinus varius)
Lat/Lng: 51.6, -2.0
OS grid ref: SU0494