https://www.sandafayre.com/They had interesting stock and good knowledge. If anything was wrong with a lot, they, quickly, refunded.
However, they were overestimating their lots. Almost all lots I bid on, I bid at a discount of 20% on the lower estimate. Almost all, I won.
Also, I do think they did not check their lots well enough: series sold as having watermark A but one or two having B, unmounted sets having mounted stamps. I do think this was unintentional.
Another thing I noticed that a very large part of items offered reappeared four to six weeks later.
In the end, the items offered at auction and their quick refunds if anything was wrong did make them an interesting source for me.