Did Town cruisers have more room for anti-aircraft additions?

Did the Town class have more room than the Crown Colony class for anti-aircraft additions?

Not necessarily. Both received broadly similar additions, but the Towns had already spent longer in wartime service when most Crown Colonies commissioned.

Both classes received broadly similar levels of extra equipment. The Towns had already fought through more of the war when Crown Colony cruisers entered service in 1940, 1941, and 1942. Their different service histories therefore matter when comparing the additions.