Confidence: It might be this.
Notes: These images seem a reasonable fit with an illustration of this species in British Bugs Gallery (Miridae). Like Stenodema, M. recticornis has a small furrow between the eyes. It also has long antennae. The present images are not, I think, inconsistent with these features – though not good enough to allow a final decision. (Is the first antennal segment perhaps too short?). The pronotum looks smooth, which seems to eliminate Stenodema.