No. 1663 Heavy Conversion Unit was based at Rufforth in Yorkshire. It formed on 2/3/43 and continued until 28/5/45.
It was a sub station to Marston Moor and the task of the Unit was to convert crews coming from Operational Training Units to fly the 4 engined Halifax bomber, when their previous experience had usually only been on twin engined aircraft. The first commander of the Unit was Wing Commander Peter Dobson DFC who had previously served with 76 and 102 Squadrons and went on to command 158 Squadron.
EB134 was a Halifax V aircraft attached to 1663 HCU. On the night in question, 3 aircraft crash landed at Rufforth putting all the runways out of action. As a result the aircraft was divereted to land at Marston Moor some 5 miles away. For some reason it finished up in Ireland as you know killing all when it crashed. The station log book was endorsed 'Aircraft went off course and in spite of all assistance, searchlight homing etc, it just disappeared'
Although it was not possible to carry out a formal investigation due to the neutrality issue, the investigating officer drew the conclusion that the aircraft had steered a reciprocal course on the compass.
If you have any specific questions about 1663 HCU please ask and I (and others0 will try to help.