Later that month Nolan stated that "he's probably been our best player all season". The next month was included in the EFL team of the week after making a "brilliant last-ditch block" to deny Wycombe Wanderers an equalising goal in a 1–0 win. On 6 February 2018, he played former club Swansea City in the FA Cup, which ended in an 8–1 defeat. Nevertheless, he scored two goals in 43 league appearances to help the "Magpies" to qualify for the play-offs at the end of the 2017–18 campaign. He also filled in as captain during absences by Michael O'Connor and the Nottingham Post reported that he had an "outstanding season". He was offered new contract by Notts County at the end of the 2017–18 season. He missed three months at the start of the 2018–19 season with a hamstring injury. Speaking in April, manager Neal Ardley stated that "he has been excellent [and] he has been part of the reason why we have looked solid at the back". County were relegated at the end of the campaign, ending a 131-year stay in the Football League. He was released by Notts County at the end of the 2018–19 season. Kidsgrove Athletic On 21 August 2019, Duffy joined Northern Premier League Division One South East club Kidsgrove Athletic. Manager Ryan Austin said that "he brings real quality to our squad as well as vast experience. We've been looking for a leader, and an organiser for a long time and, Rich fits that role perfectly". The 2019–20 season was formally abandoned on 26 March, with all results from the season being expunged, due to the COVID-19 pandemic in England. International career Duffy won four caps for the Wales under-17 team, three caps for the under-19 side, as well as seven caps for the under-21s. Duffy made his full international debut for Wales at the Liberty Stadium in a goalless draw with Slovenia on 17 August 2005. Manager John Toshack predicted a bright future for the young defender. He then played in a 1–0 defeat to England on 3 September 2005, and was said to have "acquitted himself well on the right". He further played against Poland four days later, and gave away a penalty for a foul on Kamil Kosowski, which was converted for the only goal of the game. He featured as a substitute in a 3–2 win over Northern Ireland on