just take a look at your site and see some strage urls blocked by my adblocker. Are you sure to use only static gilf files for advertisment?
If I enter your site my adblock tells me connections to:
britbike.com
adzerk.net
ajax.googleapis.com
bufferapp.com
cloudflare.com
d1zoyh6qfvajy7.cloudfront.net
dsms0mj1bbhn4.cloudfront.net
ebay.com
facebook.com
fancy.com
fbcdn.net
fonts.googleapis.com
google-analytics.com
gstatic.com
napaliprop.com
ok.ru
pinterest.com
ravenjs.com
reddit.com
shareaholic.com
tumblr.com
viglink.com
vk.com
yummly.com
The reported .swf (flash file) can be a malware. Check your server for modified .htaccess files. The name of the file looks like dynamic generated. The browser don't support Flash anymore and display the unknown extentions for donwload. This is releated to the browser of the client. But you have to find out where it comes from: your server, your ad's or a malware injection on client side.
In PC browsing with Firefox no .swf shows up on my side. It can be a injection to mobile browsers only. This can be detected by scripts.
Regards
Zarzal
