We - Kate and Mat - are cycling from London to Brighton to raise money for Children with Cancer UK. Until last November, childen with cancer was an abstract concept to us. Of course, we understood that some kids get cancer – but that happened to other people's kids.

Not any more.

Kirsty was diagnosed with a brain tumour on 15 November: a day we'd rather forget, but never will. The tumour is suprasellar (right in the centre of her head), currently considered inoperable, and his name is Terry. Around 400 children per year go through similar 'bombshell days'.

Terry had already given Kirsty's memory and eyesight a battering; she had an urgent operation at Kings College Hospital to stop him wreaking any more havoc. That was swiftly followed by the start of an 18-month course of chemotherapy. So far, so gloomy.

It's time for the silver linings, and there are so many. Her prognosis is good. She's coping brilliantly, her symptoms are under control and she's getting to school most days. Her medical care has been outstanding, and the nurses and specialists are a pleasure to meet - for us, and her.

Last but not least, we've benefited from the army of volunteers and workers from charities such as Children with Cancer UK who've been in touch to find out ways they can help that we had never imagined.

For example: every week after chemo, Kirsty threads new beautiful 'beads of courage' onto a string to represent each and every challenge she has overcome that week: from injections to scans, changes of dressing to eye tests. She's already rocking several feet of sparkly necklace. One small example of an initiative funded by this charity that makes her life a little shinier every day.

The same charity is channelling megabucks into badly-needed research. Treatment options for brain cancer, for example, have been very slow to arrive. (Kirsty's drug of choice was first licensed in the 1960s.)

You got here. The bit where we state the blindingly obvious: please help us raise money to make all of the above possible, for families like ours and those who are in unfathomably tougher situations, too.

Oh and as we're both cycling you'll need to sponsor twice…or decide who you like the most. We'll be watching.

Thank you.

Mat, Kate, Kirsty and family xx