Nothing wrong with Turner and Virr and I am sure those who have used them will continue to recommend them.
Sources for 2nd kit can be within your wing, someone selling some off, alternatively eBay is an option I know some SNCOs have used in the past - although available sizes in stock can be hit and miss
there are websites out there like RAF Tunic Jacket which tick a box
as for price anything from £30 second hand to £600 brand new tailored to fit and anything inbetween.
one option I heard people use is simply going to their parent station and asking if they have anything available. there are sometimes uniforms made which are never issued for whatever reason and sit in stores until someone the right size asks…this however is likely to be a rare case but may only cost a packet of hobnobs
I have seen in the Mess at stations adverts for those selling on their No1s which have “shrunk over time” and no longer fit…could also be an avenue although a matched size is pot luck