Numbering of "comparable" UK trade marks

The UK-only trade marks that will, if leaving the EU ever becomes a reality, be carved out of existing EU trade marks are being called "comparable" trade marks. It seems like an odd choice of word, but compared with the madness that is Brexit this is a minor quibble. The Patent Office has published a notice about how these will be numbered:

In order to identify comparable UK rights and distinguish them from existing UK trade marks, the number allocated to the comparable mark will be the last 8 digits of the EUTMprefixed with UK009.
The following examples show how comparable UK trade marks will be numbered:

Existing EU trade mark	Comparable UK trade mark
000000977	UK00900000977
000025197	UK00900025197
000340513	UK00900340513
017867542	UK00917867542

By retaining the EUTM number, we aim to keep the administrative process to a minimum.

Of course the best way to "keep the administrative process to a minimum" (let's read that as if it had the word "burden" in place of "process" - one does not keep processes to a minimum, and in any case it is surely more accurate to say it's as small as possible, not a minimum) would be to stop the nonsense altogether, but our Prime Minister is clearly dead set on it. As a numbering scheme this makes sense and is pretty simple - it reminds me of how when the 1994 Act came into operation the Registry started with number 2,000,000, which meant losing only a few numbers but provided a nice easy way to recognise "new Act" trade marks.

I wonder what will happen to comparable UK trade marks when the country rejoins the EU in a few years' time? Is the government planning for that contingency yet?