I have an SNCO friend who purchased her No 1 made to measure from them.
I seem to recall they cost her the best part of £800 (which is about right) except that, as you found, the skirt was enormous - I took 6 or 7 inches out of the waist.
The jacket was likewise, hugely oversized. Granted, people’s weight can go up and down between measuring and fitting, but there are some measurements that really don’t change - like the shoulder measurement. The shoulders of her jacket were easily 1.5" too big.
That’s a costly job to put right because it involves removing the sleeves and totally recutting the arm scye and sleeve heads, before reassembling everything and reattaching the lining.
It’s not just the RAF (and probably other services too) being mucked about, but paying private customers too.
Now, in her case I advised her to demand that they put it right - she’s paid enough for it - which they agreed to do. But they were unable to get it done before a specific event she needed them for so she came to me.
“Poor” is the way I would publically describe the situation - you can use your imagination as to how I describe it in person.