King Charles is expected to return to a “normal” schedule of overseas trips next year after his visits to Australia and Samoa proved a “perfect tonic”, a Buckingham Palace official has said.

The positive message about his health and spirits comes at the end of his biggest overseas trip since he began cancer treatment – with a more regular diary of events expected at home and abroad in 2025.

“We’re now working on a pretty normal looking, full overseas tour programme for next year, which is a high for us to end on,” the palace aide said.

Heckling by an Australian senator was said to have left the King “completely unruffled”, with him seeing free speech as the “cornerstone of democracy”.

The King was said to be a great believer in a holistic approach – of “mind, body and soul” – with his recent trip having a positive impact for all three.

Continuing to work seems to be how the King wants to respond to his cancer diagnosis. That could include overseas visits in the spring and autumn of 2025, subject to his doctors’ approval.

“He has genuinely loved this tour. He has genuinely thrived on the programme. It’s lifted his spirits, his mood and his recovery. In that sense, the tour – despite its demands – has been the perfect tonic,” said the palace official.

“It is hard to overstate the joy that he takes from duty and service and being in public and seeing those crowds engaging with communities across the spectrum. That really does lift the spirits. You can see that.”

His cancer treatment had been paused during his travels but is expected to begin again as he returns home. On doctors’ advice, the trip did not include a further leg to New Zealand.

King Charles, who left Samoa on Saturday morning, appeared to cope well with the busy schedules of the visits, with multiple engagements on many of the days, including some controversial moments.

After a speech to parliamentarians in the Australian capital Canberra he was heckled by an independent senator, Lidia Thorpe, who shouted “You are not my King”, in a protest about Indigenous people’s rights.

That was said to have left the King untroubled.

“He was completely unruffled. He’s been around a long time. As always, [he] kept calm, carried on. He believes free speech is the cornerstone of democracy, and so everyone is entitled to their views,” the royal official said.

At the Commonwealth summit in Samoa, there was an ongoing debate over whether there should be reparations or an apology from the UK over the slave trade.

But such decisions depend on the government rather than the monarch – and the King’s speech talked of learning the lessons of history.

The King was also said to have been greatly supported by Queen Camilla accompanying him on the tour.

“The King gets great strength from the Queen being there, not least when she keeps it real,” said a palace official.