One direct statement about this is in White v. Tommey  10 E.R. 483, in which the House of Lords had to consider whether to allow a rehearing of a case which they had previously decided, on the basis that there had been misrepresentation the first time round which affected their judgement. The Lord Chancellor, Lord Cranworth, said:
What ought your Lordships to do in this state of things? It was pressed very strongly on the part of Tommey by his counsel, that your Lordships in truth have no jurisdiction; that after a matter has once been heard and adjudicated upon in this ultimate Court of appeal, there is an end of it, that there must be an end somewhere, and that if it can be said that the trustees can be heard now to come and call in question the decree of 1850, what is to prevent Mr. Tommey coming afterwards, in 1860, and praying your Lordships to reconsider it again, and so toties quoties to the very end of time?
In this case, the Lords sent the case back to the Court of Chancery in Ireland, setting aside their earlier orders relating to the appeal. This did not amount to a rehearing of the merits in the House of Lords, but their correction of a mistake in the proceedings and restoring the status quo ante.
In an earlier case, Stewart v. Agnew  1 Shaw 413, another Lord Chancellor, Lord Eldon, observed:
It is infinitely better that the matter should be here finally decided upon one hearing, even if the decision is wrong, than that there should be a new litigation unknown to our proceedings, as to this matter of rehearing; - nor can any one say where it is to stop. In general, it is to be hoped that the decisions of this House are right; but, whether right or wrong, it has been taken for granted that considerations of infinitely greater moment than the considerations which arise out of the particular mischief in particular cases, have led this House to determine, that where a matter has been heard between parties at the Bar, and the House has given its decision upon the merits discussed by those parties, the House will not rehear the cause.