RFC/RAF Service Record abbreviations help needed please!

[Ottawa1880]

Hello all,

I am new to GWF having just received my grandfather's service records. I have been going through the various sources to try to interpret the acronyms and abbreviations. A large number do not appear in the lists that are online. His records are further complicated by additional notes being placed in the record somewhat out of order. His name was William Thomas Bassett born in Felinfoel,(Llanelli), Carmarthenshire in 1898. What we know is that he joined up in 1917. He had previously done a wireless course at the South Wales Wireless Training College, Swansea Branch after completing school in 1916. We have a photograph of him in the SWWTC uniform - a cool pseudo-naval uniform. I imagine that it was his wireless experience that was first called upon after he enlisted. He subsequently trained to fly BE2E's, DH4's and Martinsydes and was part of the EF (as far as I can tell). At the end of June 1918 he was injured - the family lore always suggested that he had been shot down over France. That is unclear from the records. He may have simply crashed. Regardless, he was returned to the London Hospital. Upon his recovery he was seemingly deemed unfit to fly again and he spent the remaining part of the War and early 1919 in the Air Ministry with the 1(T) Wireless School. He was dispersed 30 July 1919 at the rank of Lt. An interesting aside is that in 1941 he formed the 372 Barry (Wales) ATC Squadron serving as its first Officer in Command until 1954 at the rank of Flight Lieutenant. We have pictures of him in both his 1917-18 RFC and his post-1918 RAF uniforms

I am attaching part of his records in the hopes that the kind souls on this forum might be able to help me make some sense of this dog's breakfast!

Thanks in advance,

Paul.

[Ottawa1880]

I realized that I should have made it clear which terms I am having difficulty with - in case anyone was thinking that I wanted to have others decipher all of these forms for me. So here are the questions:

1. What was at Winchester? Was there a 66(?)w at Winchester? Could it have been the 66th Training Battalion Welsh Regiment? He was from South Wales!

2. What is meant by NTB mon. off.. Pool?

3. What is meant by NTB NEP?

4. What was the 1st N & B.D.?

5. What was the 2 A.S.D.P.?

6. What was the O.V.T.C.? What is meant by "(not Dst.)?

Thanks in advance. Paul.