Does the original BBC version exist in any release form?

Sinister Cinema has put out poor quality releases of the very rare
BBC productions of QUATERMASS 2 AND QUATERMASS AND THE PIT,the later
on a special two disk set due to its longer running time.They may be
out of print now though its worth checking for any interested party.

The holy grail however is the first film THE QUATERMASS XPERIMENT.
The buzz on this one is that only 50% of the BBC film remains. The
other 50% was destroyed in a BBC purge of their backlog. I don't
know which half the first or the last though.

What I was wondering was has anyone ever heard of a release of this
rare half a film? If it does indeed exist it should be included as
a special feature on a new release of the film proper.