That knife has been nothing but trouble for you.
I agree with Peter that you should get in touch with MAC. Although IIRC you bought your knife from a catering wholesaler in England and not MAC USA. In any case get in touch with the distributor as opposed to the retailer. Offhand I don't know who the European distributor is. "Arimoto" sticks in my mind for some reason. But perhaps not a good one.
If they won't replace your knife, you certainly have sufficient cause to be angry. The good news is that it's very easy to grind a chip out. I'd do it by hand myself, but you don't sharpen your own knives -- which makes it even easier. Any sharpener can do it.
Here's a tip: The edge MAC puts on the Professional isn't the best possible edge for the knife. When you have the knife reground, tell the sharpener that you want the edge ground to a double bevel on both sides. And that you have a very particular and acute bevel in mind. That is, a 15* edge bevel over a 10* secondary (or "thinning") bevel.
If you can't find a sharpener who will do a double bevel for you, you must find one who will sharpen to a 15* flat bevel. If you can't, you're going to have to make other arrangments -- like schlepping the knife to Copenhagen or buying Chef's Choice sharpener. A MAC "RollSharp" won't grind the chip out, but a Chef's Choice will.
Despite Dillbert's remarks, chipping isn't that common in mass-produced, western style Japanese knives. They're using better steels and not hardening as extremely. The knife steel MAC uses for its Professional series is under-hardened if anything in favor toughness over strength. Consequently it's perhaps the most robust of any mass-produced Japanese knife, and certainly highly chip resistant as those things go. Yours is one of very few chip stories I've heard.
If the knife wasn't in some way defective, and actually chipped on something it wasn't a shallot. It's could well have chipped on the board itself rather than in the food. Very hard boards can cause chipping, and so can very soft boards like nylon.
How a hard board (like stone, glass, composition, etc.) chips a knife is intuitively obvious. Soft boards have a tendency to "grab" the knife, and if the user doesn't use the knife straight up and down, it has a tendency to chip. You can actually feel the grab of the board and the ping of the chip, if you're paying attention to what you're doing at the time. FWIW, it isn't uncommon with Wusties, Henckles or other forged, stainless "German" knives. Sharpening to a "toothy" finish with a very coarse stone or diamond steel also increases the tendency to chip.
Sometimes, you end up with little rocky pieces of gravel on the board when you chop herbs, leafy vegetables -- or mushrooms (many growers use "vermiculite" to keep mushroom soil drained and airy). It's easy to chip an edge, especially when you hold the tip with one hand and rock-chop through the leaves. The action generates a lot of force. It's not the best way to chop, and a lot of us use other techniques. Or, we know we should -- but it's hard to resist one pass of running the knife through that way when you want a fine mince.
If it's any consolation I've chipped Henckles, Wusties, Shuns, and a lot of others. Even Sabatier carbon. It happens. In fact, I was having a heck of a time sharpening an antique "Nogent" style Sabatier, until a huge carbide crystal broke off (on a very coarse stone). It took a complete reprofile to get the edge back in shape, but it's been an easy knife to sharpen ever since.
Hope yours works out for the better too,