On Sri Lankan government website it says online applications for visas are no longer available since beginning of August. I've looked on other websites and it looks like a free ETA is all we need.  Justyou suggests I go to Sherpa but the last time I looked it was going to charge me about $90.  Can anyone clarify this.  I go in October 

Hi Sue,

https://www.gov.uk/foreign-travel-advice/sri-lanka/entry-requirements 

They advise that online visa applications were temporarily suspended on 2nd August. Visas can be obtained on arrival.

Hope this helps and have a fantastic tour!

Just You