As I've been job searching, listening to and reading advice about updating my CV, I've created a 1-2 page CV. I use short concise bullet point accomplishments and include those I believe relevant to the role being applied for (Programme Manager, Senior Programme Manager, Programme Director).
Recently however I have had responses from two recruiters (agencies) saying that for a role of my seniority they would expect a CV of 8-12 pages giving lots of written description of my roles and accomplishments. This seems way over the top to me but should I prepare a longer CV for more senior roles? Or should I ignore (and avoid) those recruiters?
Any advice would be welcome.

Long and Short
For what it's worth I have both. My one page resume is what I am advertising, and while my CV is everything I have done. On my CV or body of work I have every short job description (an attempt at a executive summary), and accomplishments there. On my resumes I have all of my advertising points. In addition to that in a book I have kept all of my job descriptions, and when the statement of work has changed I have kept the updated description.
Something I am also working on is documenting how I got some of the accomplishments ie if it was chance, I saw an opportunity, etc. Finally how I measured the results.
Also working on the gray area of life unsolicited feedback, from whom, when, and what I think I did to deserve it.
I hope this helps.
I'd stick with the
I'd stick with the responsibility-accomplishment 1 pager to get started. If you get the recruiters or companies interested and they specifically ask for a more detailed documentation of your working history I would give it to them then (but not initially).
I'm not a professional recruiter but I'd say that with a 12 page resume you will turn off more recruiters and companies than you will wow... a negative yield, so to speak.