On Tue, 19 Jun 2018 20:37:59 +0000, Andrew Gabriel wrote:

T5 HE and T5 HO tubes only run on electronic control gear. However,
since I don't know what your non-standard T5 tube is, I can't be sure
the same applies to that. The older T5 halophophate range could run on
magnetic ballasts, but they are rated 4,6,8,13W.

The 'new' one I want to fit was made in 2014 and is rated at 14W. The old
ones were all 20W rating.
The 'new' one runs straight off 240V so needs no fancy supply.