No experience with refurbed turbos from Latvia, but I would just buy a new core from Melett here in the UK.
https://www.ebay.co.uk/itm/391066998289
Heck, you could buy new turbine and comp housings separate and it would still come out much cheaper than £530!
Alternatively I have a 13c core and compressor housing I could sell you for £60 posted. Not used it myself although the shaft spins freely and no excess play, it came with a manifold I bought.