Any cashback incentives for changing supplier for elecrity only?

Middy

I don't have any gas connected to my flat. I have an ecodan heat source pump.

Most of these cashbacks when changing supplier are for duel fuel customers only. I am entitled to cashback like anyone else!

macman

You are not 'entitled' to any cashbacks. It's up to the merchant and the cashback company to make a commercial decision as to what to offer.
Cashback are generally available for single fuel supplies, but will generally be lower than for dual fuel.
The days of £100 cashbacks has gone, so make your tariff decision based on overall price, not cashback.
NB: I just checked-all the big 6 except BG are currently offering single fuel cashbacks.