or if it is tinned (must be in brine or water) then you can have 113g as a HEb.
But remember you only get 2 HEa's and 2 HEa's on Green or Red and 1 HEa and 1 HEb on Extra Easy (however Tuna would be free anyway on Extra Easy).
The packet of sauce of course is not free and doesnt have any free food allowance. So look at the nutritional information and you can work out by the calories using the 1 syn = 20 calories rule of thumb. But be aware that the nutritional information may only be for a percentage of the packet, not the WHOLE packet (usually a 1/4 I think). So the syns may need to be multiplied. Hope that makes sense.
If you post the nutritional information as it is written on the packet, someone will be able to accurately work it out for you.