FORMER Thornbury Bronco Billy Vunipola has vowed to heed reproachful emails from his aunties in Australia warning him to keep his cool in Saturday’s European Champions Cup final.

The British and Irish Lions number eight and his prop brother Mako will be looking to help Saracens retain the cup when the Aviva Premiership side tackle French team Clermont Auvergne at Murrayfield, Edinburgh.

Billy, who paid a visit to Thornbury RFC in February along with his brother and parents, revealed he had been admonished for letting his frustrations boil over in Saracens’ 27-25 Aviva Premiership win at Northampton last month.

Billy’s temper once famously led to local referee David Parry-Jones sending him off during a Thornbury Broncos game against Clifton to ‘teach him a lesson’ before the Vunipola brothers went onto greater things.

The usually-composed 24-year-old has admitted ‘getting flustered’ on several recent occasions, but insisted his family have quickly kept him in check.

“I haven’t been trying to be angry, I’ve just let myself get riled up,” said Billy.

“I’ve always had that competitive edge, I think it just boiled over on the wrong side there in a couple of games recently.

“It’s something I’ve kept a good lid on overall but I have to keep working on it.

“My aunties did email me to tell me off. It’s all about staying humble and remaining grounded.

“They think that in their perspective that I was acting as though I was more important than everyone else in the team.

“They told me to keep my head down, stop being arrogant and spoiled, which is good, because it keeps me grounded.

“I think it’s fun when the crowd are shouting at you, booing you.

“Because it gives you an opportunity to prove them wrong.

“There were times when I have been getting flustered, but I’m only human. But it’s part of the attraction, part of what everyone loves in a rugby match and a challenge.”

Billy, who will tour New Zealand with the Lions next month, predicted his cousins will raid the mountains of kit he and Mako received this week.

Mako toured Australia with the Lions four years ago, and Billy said: “If you went to our house you probably wouldn’t find any Lions kit.”