Are you happy with Timico?
If so there are several CPs who will supply your phone service much cheaper than the two you mention. Even if you are unhappy with Timico and want to move the broadband to Zen or IDNet the cheaper line rentals are still worth looking at.
I'm with Pulse8 broadband for line rental and AAISP for broadband.
Re email addresses, if changing supplier now is the ideal time to get your own domain and email service from a dedicated supplier, at a cost of £1.60 or less per month. See this page
for more detail. (I see I need to update the domain price on there. It's gone up a bit since 2010).
That gives you an address of your own choosing that is ISP-independent. You could literally have it running today. Start sending using it immediately, reading from it and your existing one, while you notify all your contacts and update online accounts at leisure rather than in a rush at changeover time.
The indispensable man or woman passes from the scene, and what happens next is more or less the same thing as was happening before.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. Sync 59997/15142kbps @ 600m. - BQM