Bagot
All your chronology is logical. Fire in SRS, manual engine shutdown in CLB despite the FIRE in SRS. As there were no engine out conditions met SRS successfully transfered to CLB with respective target speed (ECON CLB - 250 in your case). You started ECAM - but speed was rising, you selected it, then shutdown according to ECAM. You set TOGA and you are in an unwritten situation in FCOM.
ECAM handling is high priority in FIRE. So even accelaration altitude is reccomended to be delayed untill agent dischargment - your speed selection is good. But after that you should level off for retraction and manage speed - the target will be now green dot, no need to select it. There is no need for TOGA, but even if it is set when out of SRS, just select/manage whatever you like.
No accurate reference for your request in FCOM, some usefull only 4.04.30 p.10-16a, 4.05.80 p.1, 1.22.30 p.56a, 57.
yes, it is not good when you met something not described, and moreover when you punished for that.