Looking for a half decent one for the errand bike….nowt too heavy as it has to go on the bike…d locks any good?

Decent D-locks are the practical choice, but a lack of flexibility will limit where you can lock it up.

I use Masterlock Street Cuffs for my town bike.

I have one of these:

Trelock.

Still got the bike, it folds up small and goes round nice big posts.

APF

Was gonna suggest Abus Bordo, that Trelock looks very similar.

trelock looks interesting…would fold up into panniers quite well…thanks for that.

Personally I have used Abus for years for both mine and the GF commuter bikes.

Both have allen key security skewers, stainless steel torx security screws for stem and seatpost clamp.

You need to remove some material from the heads of the pan head security screws if they are recessed, as on most bike parts. The head form is a larger diameter to the standard ones used for bikes

Abus mini-U lock 40 for general use but obviously only fits cycle racks and smaller diameter sign posts, which are plenty around here.
I also have a Abus Granit steel-o-flex 1000 for out all day/night, doubling up locks and fits two bikes together on a rack or if I think I will need to use a lampost, and also fits round my waist.

Squire Eiger are very cheap for the protection afforded. About £25 for a Gold standard is excellent. Had one for years.

cheers tired, that looks better for my budget!