Twitter videos slow to load on wifi (mobile device)

[#1]

I've had for as long as I can remember issues with videos on Twitter being slow to start when on wifi. I've got an iPhone 6S. If I turn off the wifi and use my (EE) 4G connection the video loads without hesitation. As you can see I'm getting pretty reasonable wifi speeds. I've also experienced the same slow starting on my ipad.

Any thoughts? 

[#2]

Sorry for the delayed response, it is just Twitter you're experiencing slowdowns on or general web browsing too? If it's just Twitter it may be worth taking a look at this: https://community.plus.net/t5/Everything-else/Facebook-and-Twitter-slowdowns-help/td-p/1647480 and provide the information requested to investigate further.

[#3]

I've only noticed it on twitter. Just loading videos and some animated GIFs. I'll add my details to the link. Thanks for responding.