humming and/or grounding issues on tanglewood AS35 'fat boy'

Hello wonderful tecchy people!
I have the aforementioned guitar to fix. It buzzes when plugged into my amp with the volume up. It has 2 volume knobs for each of it's 2 pickups and 2 tones respectively (at least I'm pretty sure that's what they're for). Don't know I'd it's worth noting that this is a slightly different guitar from the normal slimmer AS35, although I have yet to find another one the same, online or off.
Now I have fully set up the housing outside the guitar if that make sense, on a bit of cardboard, as it is a sealed unit. I am an electronical ignoramus, but contrary to all the advice on this subject I have seen, there is no earth which I can see. However it has been functioning fairly normally until this problem arose, apart from a little crackle when adjusting the volumes. Now it buzzes horrendously, although there are varying amounts of improvements when I touch the various lugs, pickup switch, but not the strings. Also contrary to advice, there are no cavities to add shields to, and the only way of grounding properly it would seem is to drill a hole beneath the tailpiece and bring a cable through that. I shall take some photos to help anyone see what i am getting at if I get any response as on here, but from what I've said can anyone help? Thanks all