Existence conjecture for Hadamard matrices of 2N-type

A Hadamard matrix of 2N-type is a Hadamard matrix of order $2v$ of the block form

$$H=\left[\begin{array}{cc}A&B\\-B^T&A^T\end{array}\right],$$

where $A$ and $B$ are negacyclic blocks. 2N-type existence conjecture. For each even integer $v>0$, there exists a Hadamard matrix of 2N-type and order $2v$. Via the bijection between such matrices and NG-pairs, this is equivalent to the assertion that NG-pairs exist for all even lengths; the source gives no general construction and notes the absence of a pair of length $94$.