Growing up, Ellery's favourite team was Arsenal. His favourite player is Gianluigi Buffon. His favourite film is Inception, and off the field he also enjoys playing video games such as COD and FIFA. On FIFA, he plays as PSG. Ellery's inspiration is his mum. In the future, he wants to go sky diving and also own a Tesla!

An England youngster too, Balcombe started his Three Lions journey as an Under-18 player before he progressed through to Under-21 level. In 2017, he was part of the England squad that won the Toulon Tournament.

Making it into the matchday squad for Fulham in the Sky Bet Championship and then Notts County in the Emirates FA Cup, Ellery had a short loan spell at Boreham Wood in 2018. That move was cut short by a knee injury he sustained on international duty.

Ellery was present in Nyon, UEFA Headquarters, in December 2018 to collect England’s Fair Play Award from the U19 Championships in Finland the previous summer. While there, he also helped conduct the European draw for the U19 tournament in Northern Ireland.

In the of summer 2019, he started another loan spell with Danish side Viborg FF. That deal lasted until January 2020, when he was recalled by Brentford due to a back injury.

In January 2021, Balcombe joined League One club Doncaster Rovers on loan until the end of the 2020–21 season. He finished his spell with 17 appearances. The following six months were spent on loan at Burton Albion, also in League One, where he played mainly as a cup goalkeeper.

He then joined National League side Bromley on loan in January 2022. Becoming the regular number one keeper, he made 19 appearances on the way to the first silverware of his senior career. He made a number of saves as Bromley beat Wrexham 1-0 at Wembley Stadium in front of 46,000 fans.