screenshots attached.
To reply to your questions, the max weight value in the carrier configration page, from reading any value in there is overriden by the weights ranges so although its a issue, it cant be affecting this.
The site is live, www.everythinghenna.co.uk
for your afterthought , yes, it presents all the options, sadly, when its over the weight limit for that particular range/shipper it wont remove it (