It looks like the @ModTeam have missed this thread as they should have replied by now, hopefully they should pick the thread up soon.
Can't agree with Shaf more than the speed should be tested wired directly to the hub.
You are correct that the SH1 (VMDG 480) is now obsolete. and has a poor reputation for wireless coverage, especially if operating with marginal power levels.
Assuming you have the SH1 set to use the 2.4GHz band, 36Mbps is a typical speed for single stream wireless adapter. Speed will be further hindered due to range, your wireless environment and the topography of your home. There are some tips on how to improve your wireless signal here.
It would be worth giving retentions (thinking of leaving us option) and have a friendly chat, explaining the poor wifi, and see if you can upgrade to a SH2(ac) for a nominal fee bearing in mind it may tie you into a new contract unless discussed beforehand. The SH2 can broadcast on the 2.4Ghz and 5Ghz bands simultaneously so you can benefit from the wider, less contended 5Ghz band
You also have the option to but your own third party wireless router and use the SH in modem mode. Most decent third party routers will outperform the entry level SHs.
I would also bear in mind that wireless speed will be heavily dependant on your wireless clients, with single stream wireless N adapters managing around 35 - 40 Mbps, to MIMO wireless N clients reaching around 180 Mbps and wireless AC clienis should be able to manage 200Mbps + at close range.
Really sorry to hear about the issues experienced.
I've located your account and post-refresh the equipment timeouts previously detected have since cleared.
There is, however, a high demand for our service present in your area under the fault ticket reference F003566129, with a review set for 16/08/2017. With this, you might find that your Virgin Broadband, Virgin TV or TiVo® interactive services are a bit slow at certain times of the day. Apologies for any inconvenience caused by this.
I've sent you a private message so that we can chat about this some more.