Parents Chris and Jenny Byrne will be powered on to cross the finish line at the London Landmarks Half Marathon on Sunday, to support the Warwick charity which helped them through their daughter's cancer battle nine years ago.

The couple, from Wolverhampton, are running through the capital in aid of Molly Ollys, the children's charity that supported them following Rosie's leukemia diagnosis, in 2015.

The charity was established in Warwick in 2011 by Rachel and Tim Ollerenshaw, of Hatton Park, following the death of their eight-year-old daughter Molly from a rare kidney cancer.

During Rosie's treatment – and following two periods in intensive care at Birmingham Children's Hospital – Molly Ollys granted the three-year-old a special wish to follow in the footsteps of her favourite character on a guided Paddington Bear tour of London.

The family's life changed forever just a few weeks after Rosie's third birthday when she was diagnosed with Acute Lymphoblastic Leukemia.

Jenny explained: "She was fit and well but the day after her third birthday party we noticed she had got a limp which got progressively worse and after a number of tests and scans they couldn't really work out what the problem was.

"Eventually she couldn't bear any weight and an MRI scan showed she had lesions through the major bones in her body. They knew then that she'd got a form of cancer but couldn't determine immediately what type.

"She had no other signs of illness like infections or bruising – none of the classic symptoms you associate with leukaemia. But we were told to pray that it was leukaemia because it's the easiest cancer to treat."

Chris added: "It's like the rug had been pulled from underneath us. Everything came to an end and normal life just stopped there and then. We felt like we were in a black hole. You don't ever think something like this will happen to you, it always happens to somebody else - but it did happen to us and it was an incredibly hard time."

Rachel Ollernshaw with Olly the Brave (image supplied)

A three-year treatment plan got under way immediately, including regular chemotherapy, scans and blood tests. And it was during the darkest of those times that the family found Molly Ollys as Rosie fought for her life during two periods in intensive care – in close succession.

Jenny, who is headteacher at SS Peter & Paul Primary in Wolverhampton, said: "We started reading a Paddington Bear book she had chosen while she was in intensive care in the hospital ward, thinking she may be able to hear us. When she came round she remembered it and even knew where we were up to in the story and wanted to carry it on - and that started a great love of Paddington Bear for her.

"We thought we were very lucky that she is still with us and, for her and her brothers, we ought to make some special and lasting memories because she was so vulnerable."

In 2016 Molly Ollys organised an overnight stay and Paddington Bear tour of London for Rosie and her family, including Portobello Market, Paddington Station, the station café and London Zoo, which also featured in one of the books. They even gifted Rosie a kiddy camera to help document her trip.

"She was in her element. You could tell how special she felt. It made such a difference to her. This incredible, selfless, family-oriented charity made a significant impact on the whole family at a time when we all needed it most," added Jenny.

Rosie also became the proud owner of one of the charity's mascot toy lions – a therapeutic cuddly toy called Olly The Brave. Olly has his own Hickman line and a detachable mane which helps to explain and normalise the effects of chemotherapy. These also form part of an Olly The Brave pack that has now been handed out to more than 40 hospitals, along with a book from the charity's exclusive Olly The Brave series.

Rachel Ollerenshaw of Molly Ollys, recalls: "Rosie's wish to follow in the steps of Paddington Bear is one that I will always remember, such a lovely thing to ask for. I had the pleasure of meeting Rosie and her family in 2015. They have been very supportive over the years and we are so grateful. Wishing Jenny and Chris all the best for the run at the weekend."

Today, 12-year-old Rosie has not looked back since ringing the bell at BCH to signal an end to her treatment in May 2018. A student at St Edmunds Academy, today she enjoys an active lifestyle, including Park Runs and playing for her local cricket team. She also took part in last month's Wolverhampton 10k.

But Jenny and Chris have vowed to never stop 'giving back' to the charities which helped them during the most challenging chapter of their lives together and they're looking forward to hopefully improving on their time at their second London Landmarks Half Marathon on Sunday.

The event, organised by baby charity Tommy's, sees runners follow a route from Pall Mall to Downing Street, passing Westminstger Bridge and a series of landmarks on the way. It has raised more than £37.5m since it began in 2018.

"We've trained together more this time so we're looking to enjoy it more. It's a great event with a spectacular route and lots of different entertainment and last time it was big physical challenge to get around it and didn't appreciate the atmosphere and how amazing it is to do it in London. This time we're hoping that we can take it in a bit more and it will be really special," Jenny said.

To sponsor Jenny and Chris visit their JustGiving page.