Tried re-running again, gives out of memory error -
root@OpenWrt:~# wget http://vanquishsolutions.co.uk/openwrt/VG3503J/update.sh && chmod +x update.sh
&& ./update.sh
Connecting to vanquishsolutions.co.uk (104.28.29.73:80)
update.sh 100% |***************************************************| 1058 0:00:00 ETA
Connecting to vanquishsolutions.co.uk (104.28.28.73:80)
index.htm 100% |***************************************************| 18626 0:00:00 ETA
LuCI Status: Updated /usr/lib/lua/luci/view/admin_status/index.htm
Connecting to vanquishsolutions.co.uk (104.28.29.73:80)
root 100% |***************************************************| 59 0:00:00 ETA
Crontab: Added /etc/crontabs/root
Connecting to vanquishsolutions.co.uk (104.28.28.73:80)
dsl_control 100% |***************************************************| 1744 0:00:00 ETA
dsl_control: Updated /etc/init.d/dsl_control
Connecting to vanquishsolutions.co.uk (104.28.29.73:80)
lantiq_dsl.sh 100% |***************************************************| 18711 0:00:00 ETA
lantiq_dsl.sh: Updated /lib/functions/lantiq_dsl.sh
Connecting to vanquishsolutions.co.uk (104.28.28.73:80)
distfeeds.conf 100% |***************************************************| 645 0:00:00 ETA
opkg feeds: Updated /etc/opkg/distfeeds.conf
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/base/Packages.gz.
Updated list of available packages in /var/opkg-lists/chaos_calmer_base.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/base/Packages.sig.
Signature check passed.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/luci/Packages.gz.
Updated list of available packages in /var/opkg-lists/chaos_calmer_luci.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/luci/Packages.sig.
Signature check passed.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/management/Packages.gz.
Updated list of available packages in /var/opkg-lists/chaos_calmer_management.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/management/Packages.sig.
Signature check passed.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/packages/Packages.gz.
Updated list of available packages in /var/opkg-lists/chaos_calmer_packages.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/packages/Packages.sig.
Signature check passed.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/routing/Packages.gz.
Updated list of available packages in /var/opkg-lists/chaos_calmer_routing.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/routing/Packages.sig.
Signature check passed.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/telephony/Packages.gz.
Updated list of available packages in /var/opkg-lists/chaos_calmer_telephony.
Downloading http://vanquishsolutions.co.uk/openwrt/VG3503J/packages/telephony/Packages.sig.
Signature check passed.
Collected errors:
* gz_open: fork: Out of memory.
* pkg_hash_add_from_file: Failed to open /var/opkg-lists/chaos_calmer_routing: Out of memory.
Connecting to vanquishsolutions.co.uk (104.28.29.73:80)
munin-node 100% |***************************************************| 28549 0:00:00 ETA
muninlite: Updated /usr/sbin/munin-node
root@OpenWrt:~#
EDIT:
OK a reboot seems to have resulted in a successful script execution, I was just avoiding rebooting the modem until I really had to.