Watch List notes:

Richard II (1377-99), Halfgroat, Tower, Post-Treaty/type III mule, 1.91g, 5h, m.m. cross pattée, + edwardvs rex angl z franc, saltire stops, lombardic ns, rev. + posvi devm adivtorem mev', saltire stops, civitas london, reverse-barred ns (DIG PT6/1-ii; LAL obverse 21; Potter III-9/IIIa; Doubleday 659, same obverse die; Stewartby IV, 1197, same obverse die; N.1324 [1290/1323]; S.1684 [1640A/1683]), same dies as last, slightly short of flan, otherwise good fine, rare.
provenance
Clarendon, part I, Bonhams, 28 March 2006, lot 443 - £500 [this ticket notes only 5 examples known, 3 in institutions, the Stewartby collection, and this coin. This corpus should be reviewed in light of recent auction dispersals]
Estimate: £300 - £400