Oh dear OP, that is a beautiful piece of wood. You can re finish a wooden worktop very easily yourself. Buy a random orbital sander, and a cheap wet and dry vac (should come to less than £150). You can buy a Triton wet and dry vac from Screwfix for about £40, and I redid my worktops with a 5 inch Bosch sander that cost me £70 but I would go for a more expensive one with more power of I was going again. A packet of sand paper is about £5 off Amazon.
Clear the work tops, connect your vac to your sander, and then start sanding back at 60 or 80 grit to strip back the old finish. Keep going in an even pattern (don't gouge the worktop) until all the marks are gone.
Once the Worktop is stripped, use a finishing grade of 120 grit to get a smooth finish. If you can see too many marks from the earlier sanding, use white spirit on a rag to raise the grain (wipe it over the sanded surface and it will make it rough again). Then go over it with the 120 grit until it's smooth. Once that's done to your satisfaction, get a clean DRY rag and get as much dust off the wood as possible.
Then get your finish of choice and apply- I prefer osmo polyx hard wax. It looks lovely, and it's very easy to apply, but it doesn't have a stain, so if you want to colour it you'll need to choose a stain to stain it first.
The finish time depends on what you use. I did my worktops while my wife was on holiday with the children. I did each coat with 24 hours between. Now 1 year on the finish looks perfect except where my daughter drew on it with Sharpie 😖😖😖😖😖😖😖