From the related discussion, one impediment is that the UK participates in the F-35 program, and part of what is sent to Israel are components of those planes. If the UK were to stop sending those unilaterally, the US could in extremis kick the UK out of the program, like it happened to Turkey (when they displeased Washington).
Anyhow, it appears that direct exports from the UK are relatively low, these days:
with arms exports amounting to £42 million in 2022, it is not one of Israel’s major suppliers.
OTOH from the same piece
The Netherlands court of appeal ruled in February that the Dutch government must discontinue its sales of F35 fighter jet parts on the basis of its obligations under the UN arms trade treaty.
But so far the US has not taken any extreme measures against the Dutch because of that. OTOH if Trump comes to power... AFAIK he's never questioned the usefulness of Israel as a US ally, but he did question that of NATO.