The definition of 'renovation is; " "renovation" in relation to a thermal element means the provision of a new layer in the thermal element or the replacement of an existing layer, but excludes decorative finishes, and "renovate" shall be construed accordingly". The regulations require anyone renovating a thermal element to submit a B/Notice (or even Full Plans if they preferred) to the local authority before commencing the work. So, yes.
Or you could (like ~99.9% of the rest of the population) ignore this requirement in this case, and (like those 99.9%) suffer no repercussions.