I know you have to call Vodafone so a "Tier 2" can  disable DHCP remotely on an SHG1500. I've tried this, and it failed. (I can post the various text and Twitter DMs they sent me about it if it would help). I'm looking for an alternative solution.

I've recently moved to fibre which means Vodafone sent me a nice new HG659 router to replace the old SHG1500 that they sent me when I set up ADSL with them.  When I was on ADSL, I used the SHG1500 as modem/router/wifi AP in my house.  To extend wifi to my shed/back yard, I ran an Ethernet cable to the shed and used an old router (Dynalink, I think) with DHCP disabled and fixed IP address as a second AP. It would be very useful to me if I could replace the Dynalink with the SHG1500 (mostly because you can plug a USB drive into it).

Of course the problem with my plan is that I can't turn DHCP off on the SHG1500 and, it seems, nor can Vodafone (at least not remotely while the SHG1500 is connected to the HG659).

Does anyone have any clever ideas regarding other ways of disabling DHCP on the SHG1500? (Other than going out and buying another piece of kit)