BA not responsible for the cleanliness of their aircraft?

We travelled from South Africa, via London, to Bermuda and from Boston back to South Africa on BA Club World.

My rating refers to the Customer Services Department of BA and to one particular flight that my husband and I took, BA 2233 from Gatwick to Bermuda, on 01 June 2018.

This was a special trip to visit my son and we had specially arranged the snuggle seats.

After takeoff, I lowered the footrest to find that it was covered with dried vomit. On closer inspection we found vomit splattered as far as the table on my husband's side of the "snuggle area". The cabin manager was most apologetic and moved us to seats that also had to be cleaned, (bread crumbs over the seats), and were across the aisle from one another, no longer together.

The cabin manager was sure that we would be offered some form of compensation for the experience which we found not only to be quite revolting but a health issue and certainly spoilt the start of what was meant to be a very special trip.

On return from the trip I emailed BA customer services and received an apology and an assurance that BA would investigate the issue in an effort to improve the cleaning services on their aircraft. After a period of ongoing correspondence with customer services I eventually received an email which stated that as BA was not, in this instance, responsible they could not offer us any compensation.

I fail to understand how BA is not responsible when the ticket was bought from their airline, we travelled in their aircraft and were attended by BA fight attendants.

I remain a very dissatisfied customer and am amazed that what was such a disgusting health issue can be brushed aside by BA as "not their responsibility"

Photographs can be provided.