After many attempts to get an answer following solar panel installation and switching to eon to obtain a seg export payment.

The short answer - No. You are not legally required to have a smart meter but...

a/ You may get cheaper tarrifs or occasional rewards/ cheaper short term tarrifs if you do have a smart meter.

b/ If you do get solar panels and wonder why your old non smart meter is whizzing backwards you should hopefully decide to have a smart meter so you can get paid through am export tariff for your surplus energy. There are conditions though, too lengthy to list here.

c/ If you are lucky you wont get the installation engineer who likes to lecture about health and safety for 30 mins. If you had him you know what I mean.

d/ Is there any alternative to a smart meter (particularly as you may have to send a photo of your not too smart smart meters read out to obtain your payment).
Well here is the answer I got but from Eon but I am certain there are stories out there as the ground rules seem to change regularly !

Received today from Team Radiance

'To apply for SEG you would need a smart meter at the property to record your export reading. In cases where a smart meter is unable to be installed as a working smart meter, we can also install a meter in ‘dumb mode’ in which the meter wouldn't work as smart but would record the export from the solar panels to work with the SEG scheme.
To apply to SEG you would need an approved meter that records export, there are also standalone export meters. But you would need to purchase/discuss this with a separate company.'
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- Everything is on a journey to somewhere - Gerald diPego