Birmingham Family Weekend Advice

Hi everyone! Hope everyone's well. I don't normally really post this kind of thing but I'm having a bit of trouble and none of my friends are really able to help me so I thought I'd ask the ever wise people of the internet. Basically I am trying to book a weekend trip away to Birmingham with my family in order to go and see some of my cousins. I'm really excited for the trip because I haven't seen my cousins in years and I know there's lots of things to do in Birmingham (the kids are very excited about the Sea Life Centre and Cadbury's World). However the only problem is im struggling to find somewhere good to stay for 5 of us (myself and my husband and our three kids). Lots of hotels simply don’t cater to our party size and we simply can't afford suites or anything like that. I know there's air b n b but I haven't seen one on there yet that I like and that's in a good central location! I was really wondering then if people knew of any good family places that we could stay? I'm really at sea here so any suggestions would be fantastic. I did actually red about a place called 'Staying Cool' - has anyone used them or could anyone tell me more about them? Are they good family places to stay? Anything anyone could tell me would be fantastic! Thanks for the help everyone x

(oh this is the website for the staying cool place if people don't know who I'm on about:  https://www.stayingcool.com/serviced-apartments-birmingham/?utm_expid=33777314-3.s5HsKQNDR2WOxEU7SKZTCA.0&utm_referrer=https://www.google.co.uk/ )