Sefton Park, Liverpool - What to do with kids?

Hi. I'm hoping there might be some of you on here who can help. We're going to a wedding in Liverpool this weekend and my in laws are coming to look after the kids (19 month old and almost 3 year old). We live in Bedfordshire so no where near Liverpool. Our accommodation is right next to Sefton Park as the wedding is at the palm house. Does anyone know if Sefton Park is kid friendly? Could you spend a few hours there entertaining the kids? Just trying to plan what my in laws can do with the kids. Thanks so much!