After checking, we find none other than Geoffrey Palmer was made a PEER during service as the Kings Attorney. Palmer was an anomaly from the Restoration Sir Robert Buckland gives detailed written historical evidence here: https://www.robertbuckland.co.uk/news/history-and-role-law-officers
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The position is a servant attendant role to a complete House of Lords assembly. Peers would never act as servant or attendant. Recent developments in standing orders of the Commons provide for attorney generals being members of that house to deliberate in standing committees on legislation in the commons & in privileges & standards of that house. Buckland does not mention Labour, Tony Blair, Mostyn, Goldsmith or Scotland. In 1999 the Press claimed no peer has served the position since the 1700s