Things I have learned:
1) Granite is heavy, but not too bad to move.
Fortunately this country doesn't go in for the American trend of gluing worktops down. Upstands took some care to remove without snapping (we didn't end up breaking any pieces of granite in the whole procedure). Saws and multitools didn't do much for cutting the silicone, but wallpaper scrapers and blades worked ok, combined with a mini prybar. Too late I discovered what I should have bought - a flexible knife used by potters for removing pots from the wheel.
There is no substitute for brute strength. A team of people with clear instructions and carrying is better than wheels or suction cups.
2) Granite is dead easy to cut.
The little GMC wet saw was amazing. Cut 30mm stone with ease. Don't try and use a metal straight edge as a guide - grit or debris can get underneath and the vibrations can cause big scratches that are difficult to remove (more on this later!). Use a paint marker pen and freehand cut. Any minor wobbles can be cleaned up later with polishing pads.
3) Granite polishing is simple, but boring and incredibly messy.
We had to make multiple cuts and most of them needed polishing. ATS diamond tools were amazing, really helpful advice and great products. A set of their economy polishing pads did the whole lot. There seemed to be a bit of a knack to using them. They need to be wet, but seemed to work best just on the balance between wet and drying out. Too much water and it was hard to keep track of what was happening. It was mostly like normal sanding, but the consequences of missing a scratch at an early grit feels much more frustrating! We used a cheap rotary polisher and a very gentle dribble of water.
It is hard to match the finish on a top surface exactly, especially if removing long straight scratches. Even with a 3000 grit pad followed by polishing compound, it looks slightly different from the factory finish. This is probably due to the colour enhancer they put on worktops in the finishing process. MB granite polish was good, but not magic.
We were enjoying the process so much we bought another set of worktops off eBay for £50 to do the utility and an extra run of wall cabinets turned into floor cabinets. Even if the name of the stone is identical, you will see the difference if you look closely. I tried various stonemasons though and their matches were no closer.
Overall the total cost of the saw, polisher, backing pads, diamond pads and diamond holesaw was about £200.
4) Drilling big holes for taps or internal corners is easy
Diamond hole saw from Screwfix did a great job. You need to be careful when starting, but with a bit of patience it was great
5) Polishing internal corners and plunge cuts is hard
We got ambitious and wanted to make a cut out for a Belfast sink for the utility. Polishing a slightly shoddy plunge cut flat was tedious. Polishing the internal corners, even with a flexible backer pad was really tedious! This was probably the only bit that was really difficult, and should probably have practiced first. We got away with it and it ended up looking great, but it could have been a disaster.
We also had to enlarge the sink hole to put a bigger sink in the kitchen bit. We did this in-situ as we didn't want to weaken it too much. Cut outs done by professionals have strengthening bars epoxied either side to prevent it snapping and we were going beyond this. Cutting in situ makes a mess!
6) Granite epoxy sets really fast!
Nothing like pouring epoxy. Make sure everything is set up perfectly in advance and move fast! We found masking tape either side of the seam and smoothing it down as neatly as possible really helped. You want as little as possible needing polishing off so as to minimise the area that needs refinishing.