Have you looked at using a data only plan for the sim you dont want calling features on?
Something like this http://giffgaff.com/...obile-broadband £12.50 for 3gigs isnt a bad deal really.
I presume any data only sim would work, for example a one ment for a 3g dongle, although you probably need to check the terms of service as some providers are a bit sniffy about what device you put their data sims into (Its very unlikely they will bother doing anything if you do use it in another device though, iv certainly never heard of anyone getting their sim blocked doing this).
So have one sim for flatrate calls/texts with data disabled in the sim settings and the data only one for the internet connection. Most duel sim phones have a 2g and a 3g sim slot, so you probably dont want internet enabled on the 2g slot anyway.
Hope this helps......
Edited by maniac_mouse, 16 December 2013 - 10:00 PM.
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