306 Heater Matrix bypass: Do I cut the pipes and use (what size?) copper pipe?

Hi, if anybody has done a 306 heater matrix bypass, do I need to cut the two pipes and join them on to a copper pipe with jubilee clips?

If so, can you remember what size copper pipe?

If I ha not to cut the pipes, whats the best method? any help appreciated, I would like to have it done by the coming friday in 6 days. Cheers!