Bought the bike last back end and just contacted Datatag to re-register the bike.
They say they cannot because of not having the original registration form, which i don't have.
They can supply me with a subsidised set of 5 transponders and a new registration form for £25. which sounds reasonable.
May seem silly questions but how big are these transponders and where do i put them and if it has been registered previously won't it have transponders already on it, do i remove them and where are they

I have asked them this question and they haven't replied, don't know why.