The group rated the longest day of the journey, however, as their favourite.
“We did 195km (121 miles) and it was to go from Hungary into Serbia in one day,” said Mr Redwood.
“We passed through so much scenery, so many dogs, so many awesome little towns, many hills.”
He said the warm welcome they received at the Serbian border made the day stand out.
They completed the cycle ride in 26 days, clocking up a total of 3,184km (1,978 miles), and finishing at the Blue Mosque in Istanbul.
They have so far raised £4,700 towards their target of £5,000, which will be split between Macmillan Cancer Support and Alzheimer’s UK.
Talks about a fourth trip were now underway, they said, but details had not yet been settled.