Is pizza oven fuel safe for use in the egg?

Interesting. But it's a wood product that has not taken the magical transformation; carbonization. So it's raw wood in a convenient package, very clean burning, very dry, burns uniformly. A by product of the wood manufacturing industry, my guess. Sawdust from beech lumber.
The egg burns lump charcoal. If raw wood is burned in the egg it will smoke like a house on fire unless there is enough air to fuel the fire to a Flame. A flaming fire is very difficult to control to a target dome temp.
That's why carbonized wood, lump charcoal, is the best and should be the only fuel for the egg.
That's my advice. Best of luck.

Assuming that this fuel burns more or less like wood, you will find it doesn't work very well. I burned some regular wood chunks in my small Egg once. Either the temperature was low and it produced incredible amounts of smoke and creosote (the daisy wheel was almost permanently stuck on after a very short burn), or if the temp got up to where the wood ignited, then the temp soared through the roof. If you want to burn wood in a closed cooker, you need to burn it down to coals in another vessel and then shovel the coals into the cooker.

As for "safe", you will be in control of the temps and I doubt you would want to burn this fuel at temps like it might be capable of, so I can't see it being unsafe.

Hi I'm a fellow UK egger. I agree that charcoal is best. I found it initially hard to source good quality charcoal but now buy "Restaurant" charcoal from Booker's. It comes in 12kg bags, I suppose for use in a Tandoori oven. Booker's is a cash n carry so you do need some proof of a business or charity to get membership - it's not a very thorough check though!