Search Button Not Working On Mobile Browser

Hi... Been working through creating a store using the default store theme for version 2.3.0.2
Loaded all the affiliate products into the store and all works a treat along with url redirect on the add to cart button and just before I start to make it look prettier I thought I'd do a thorough test.
Now, when I view on a mobile browser (in my case android) the top header search button doesn't perform the search function. Looked through a great deal of forum posts on here all pointing towards the search module has been moved out of the <header> and/or the common.js defined #header instead of #search. Checked all these out. Reloaded the default theme completely from my back up and still no joy.
I'm obviously missing something but can I find it, No.
Feeling deflated I haven't sorted the issue myself but I have exhausted my options with no alternative but to ask for help peeps. My test store url is www.shop4petsupplies.co.uk using Version 2.3.0.2. Any help/advice/pointers/ will be much appreciated... Cheers Peeps

Seems to work here using android.......type in classic and hit the search button and get a list of products with classic in title.
type in mini and hit search and get list of products with mini in title.
Have you cleared your browser cache or is it something else thats not working