A mishap in the workshop left me with a broken outer gear cover/door and a smashed inner cover/door hinge on my 30.5mm bore long bed Super7 yesterday.
Although a second hand outer cover/door can be had for around £70, the inner is genuinely unobtainable short of buying a lathe and parting it out.

Enter Alutite Aluminium Welding Wire, along with a Mapp gas torch, a stainless pointy tool, stainless wire brush and some welding clamps.

I can't recommend Alutite highly enough, it's brilliant!