let
    W = (x)=> Table.FromRecords(Json.Document(Web.Contents(x))),
    T = Table.FromRows({
        {"gold_am", "https://prices.lbma.org.uk/json/gold_am.json"},
        {"gold_pm",  "https://prices.lbma.org.uk/json/gold_pm.json"},
        {"silver", "https://prices.lbma.org.uk/json/silver.json"}
    }, {"Name", "URL"}),
    TR = Table.TransformColumns(T,{"URL", W}),
    Expand = Table.ExpandTableColumn(TR, "URL", {"d", "v"}),
    Tr2 = Table.TransformColumns(Expand, {{"v", (x)=> x{0}}, {"d", Date.From}})
in
    Tr2

let

    Source = {
        [Name = "gold_am", URL = "https://prices.lbma.org.uk/json/gold_am.json "],
        [Name = "gold_pm", URL = "https://prices.lbma.org.uk/json/gold_pm.json "],
        [Name = "silver",  URL = "https://prices.lbma.org.uk/json/silver.json "]},

    get = (x) => [json = Json.Document(Web.Contents(x[URL])), 
                fields = (y) => 
            [Name = x[Name], 
            Date = Date.From(y[d]), 
            Usd = y[v]{0}],
            res = List.Transform(json, fields)][res],
    ltr = List.Transform(Source, get),
    tbl = Table.FromRecords(List.Combine(ltr), type table[Name = text, Date = date, Usd = number])
in
    tbl