As featured in the Times last week, the Tunbridge Wells rider was taking part in the 128cm competition – the height of the fences – with her pony Gelvin Castle Grey.
Her mother Lucy van den Broek was thrilled with the display and said: “It was my proudest moment when the girls were standing on the podium for the prizegiving with the National Anthem playing.”
She described the events of a dramatic weekend, saying: “Flo had a selection class on Thursday as although five are always selected, the Chef d’Equipe has to then select four from the five.
“This is done on performance in the selection class, ie. least number of faults, style and performance, and Flo and three of the other riders got selected and one got dropped, which is quite harsh.”
She continued: “On the day, they do a course walk altogether with the team Chef d’Equipe to discuss strategy.
“They parade with the England flag and then each team member from England, Wales, Scotland and Ireland jumps.
“Each round has points for whatever has been done or hasn’t been done correctly, and this is done twice.
“If two teams are level in points after this, then one team member from each of those teams goes head to head in a jump-off to get the quickest round.
“Luckily England were quite a few points up on Scotland, who ended up with silver, and the rest of the teams so we won without having to even do the jump off.
Last year Florence won the 11-and-Under National Championship at the age of nine, and qualified for the Horse of the Year Show at the NEC in Birmingham and the Mini Major at Olympia.
The Beechwood Sacred Heart pupil will now try to qualify for the two showpiece events again, with the Welsh Home Pony International and the nationals respectively.