Also well worth a read:

As all readers of this post will know, the United Kingdom gave notice of its decision to withdraw from the EU on 29 March 2017. Under Article 50 TEU, that means that (subject to a different date being provided for in a withdrawal agreement or an extension by unanimity) the UK will cease to be subject to the Treaties on 30 March 2019.Unless any different provision is made in a withdrawal agreement, the Court of Justice of the EU will cease, on that date, to have jurisdiction to rule on questions of EU law referred to it by UK courts under Article 267 TFEU.Since the Court of Justice takes between 12-18 months to answer a request for a preliminary ruling, parties to litigation that raises questions of EU law may well be concerned that, unless a reference is made soon, there will be a serious risk that any reference will not be answered before Brexit day and so will never be answered. If parties think that the CJEU is more likely to give a favourable answer than the UK courts, they will want to accelerate the making of a reference so that it happens now or in the next few months, to avoid any Brexit risk.

Source: Is the triggering of Article 50 a good argument for making a reference to The Court Of Justice now? – Monckton Chambers