Holts have a Lebeau-Courally (whatever that is) side-by-side 9.3x74R with additional 20 bore barrels coming up for sale in September:
https://auctions.holtsauctioneers.c...alelot=A0921+++1250+&refno=++166591&saletype=
Estimate: £8,000 - £10,000. Note to buyers - Holts charge an outrageous 32.7% buyer's commission AND this lot suffers from 20% VAT to UK buyers.
On the other hand, they also have a buggered-about with Rigby rising bite, re-chambered from .450 to .470 (why?!) and restocked. Estimate £5,000 to £7,000. Same additional costs as above.
https://auctions.holtsauctioneers.c...alelot=A0921+++1200+&refno=++166134&saletype=
Bearing in mind that a new Rigby .470 rising bite will set you back £120,000 before options, buying from Mr. Holt is probably quite a good deal.