Actually, it's the other way around. It's ridiculous to have a massive load of missiles without a top-flight radar. Based on the detect-to-engage sequence and most likely combat scenarios I'm confident a potential loadout of 96 ESSM and 24 CAMM are going to defend the ship just fine. How many missiles are you expecting in a saturation attack against a Canadian Task Group anyways? Pick a number and do
the math backwards (pg 129) and find out how many missiles you need. It's not as many as you think.
It is far more likely that a ship is hit by a missile it didn't detect, didn't identify in time, or couldn't track than it is for a ship to be overwhelmed by 20+ enemy missiles.
De Zeven is a specialized AAW frigate designed from the ground up to carry more missiles. Type 26 is a specialized ASW frigate, which is trying to be modified to make it a GP frigate. There are lots of things the Type 26 can do that the De Zeven is unable to do because of the design differences.