The teaching is purely sessional, so yes, I would be invisible I guess. Still negotiating exactly what my role would be, but initially, I can't envisage it being more than 4-5 hours a week.

The admin role would be a student support position in a department relevant to my PhD, liaising with postgraduates and offering academic and clerical support.

Hey Mr. Dr. - Reading your thread with interest. I just finished a stint in student services admin and found it very illuminating. Like you I have an abundance of HE lecturing work on my cv. But it was great to see things from the other side. Not sure how these things pan out in terms of academic employment. But surely working with students and academic processes in your field is better than not doing so. I think my time in student services will make me a better lecturer. It would certainty make me a better head of department.

Also my own research was much easier in the admin job. Less money stress and a 9-5 routine with comparatively little responsibility. It's true that universities hire from within existing teaching teams. But it's also true that you can hang about for years having the mickey taken and going nowhere.

Good luck!