Well you are in limbo-land as you don't have an EASA licence so cannot convert with SOLI and you don't yet have a UK CAA licence. Go ahead and try but I think you will find out what I have just wasted 2 weeks of my life to discover. You still have an ICAO licence so can apply for validation of that in most countries outside EU but in terms of EU employment where you need an EASA licence, your UK EASA licence at the moment is worthless as it is neither EASA - nor UK as yet.