Hmm.. Just realised my workaround kinda sucks..
Went from 
```rust
where
    Provider: CryptoProvider
```

to
```rust
Provider: CryptoProvider,
    SignatureSize<Provider::SignatureCurve>: ArrayLength<u8>,
    <Provider::SignatureCurve as CurveArithmet½ic>::Scalar: SignPrimitive<Provider::SignatureCurve>,
    SigningKey<Provider::SignatureCurve>: DigestSigner<<Provider::SignatureCurve as DigestPrimitive>::Digest, ecdsa::Signature<Provider::SignatureCurve>>,
```