I know what your mean about their website - not that clear. Fees for 6th form are roughly £10.5k per term for boarders and £7k approx. for day pupils. This covers all vocational and academic tuition. So yes A levels are included.
Those figures are assuming no DADA is awarded ie full fees payable.
A DADA is assessed on your household income and is divided into a contribution towards fees and a contribution towards housing costs. You can see from the figures above that boarding in 6th form boarding houses is approx. £3k per term.
Not everyone gets a DADA - these are decided at audition and awarded on merit. If you look at the government website with guidance for DADAs you will see what your contribution to the fees would be, if your DC got both a place offered and a DADA.
https://www.gov.uk/government/publicati ... ome-scales
As for schools offering dance and A levels at the level 6 diploma level like Tring - the ones I know are Elmhurst (Birmingham), Royal Ballet School (London), Hammond (Chester), Central School of Ballet (London - A levels + BA Honours degree). I think there is Legats too and I am sure there are others. Otherwise you are looking at colleges offering the level 3 qualification (equivalent to 3 A levels) where sometimes A levels can be studied alongside. I know this is the case at BOA (Birmingham) but not an area I know anything about.