Plumbing - 22mm vs 21.5mm overflow pipe with 21.5mm joiners?

This question is relating to plumbing materials not an actual plumbing problem. I've made some flyball hurdles using 22mm overflow Push Fit pipe and 21.5mm T connectors. The 22mm pipe fits incredibly snugly into the 21.5mm connectors which is absolutely fine. I'm thinking of making some more and this time have found cheaper piping...but its 21.5mm in diameter. Will the 21.5mm piping still fit as snugly and firmly into the 21.5mm connector or will it be easily pulled out and twist within the connector? I'd be committed to purchasing 30m at a time and don't really want to order it and hope for the best. I'd also like to avoid using adhesive because I'd like them to be 'collapsible'. Any help appreciated, many thanks!