NEC ECSC: is W1 a default option outside UK?

Contract Data on an NEC3 ECSC has been left blank. The main NEC3 ECC applies W1 for dispute resolution.
There is no “flowdown” clause.
W2 not applicable in this jurisdiction.
Does W1 apply by default in the subcontract, or is there in fact no Dispute resolution option adopted?

I assume you are referring to the Engineering and Construction Subcontract (ECS) rather than the Engineering and Construction Short Contract (ECSC).

Although the W Options are perceived to be optional, the intention is that they are not and one of these is chosen. In NEC(1) and NEC2 the dispute resolution procedure was part of the conditions of contract at core clause 9.

If the contract data doesn’t state a W option then none would apply, regardless of what was in the main ECC contract., as they are discrete contracts. In this instance you would be required to refer any disputed matter to the applicable legal process which applies in the jurisdiction under which the contract is subject to.

Acronyms will be the death of me.
Thank you.