>Have created a report variable (character) which sums string values over multiple records. It's too short to hold the sum in some cases. How can I get around the apparent 255 character limit, please?

What exactly do you mean?

There is a nice simple trick to put related info together without using + sign, but rather using ;

see Re: Creeping (downward) 'Page header' band Thread #1174906 Message #1174964