Unfortunately, the series was rushed and Wilmer didn't enjoy the filming at all.
The scripts came in late and some of them I rejected and rewrote myself. They went straight into the waste paper basket; I simply refused them. The Red-Headed League had fourteen characters that don’t exist in Doyle, and I said no way. This is not on. And they all sounded when I read the script – before throwing it into the waste paper basket – as if they’d been borrowed from Damon Runyan. One was called Harry the Horse.
When the BBC decided to produce a second installment in 1968, Wilmer was approached to return but he turned them down. After a search involving putting out feelers to John Neville (who had earlier portrayed Holmes in A Study in Terror) and Eric Porter (who would go on to play Professor Moriarty in the Jeremy Brett series of Holmes adaptations) Peter Cushing was finally signed to the role. Cushing himself had previously assayed the role in Hammer pictures' The Hound of the Baskervilles.
This new series, given the slightly different title of Sir Arthur Conan Doyle's Sherlock Holmes, was to be filmed in full color and expanded to sixteen episodes. While Nigel Stock returned as Watson to accompany Cushing, they were given even less rehearsal time than Stock and Wilmer had been granted. Supposedly, this was an annoyance to Cushing and he didn't enjoy his performances in the series.
Having viewed the only six episodes which remain of the Cushing series, (back then it was commonplace for the BBC to wipe tapes after airing and unfortunately it appears that ten episodes of the Cushing series suffered this fate) I would beg to differ.
A&E and BBC released a three DVD set of the six existent episodes:
The Hound of the Baskervilles (a two-part episode)
The Sign of the Four
The Blue Carbuncle
A Study in Scarlet
The Boscombe Valley Mystery
Obviously, Cushing had taken a stab at Hound a decade earlier with the Hammer version. With what I assume was a fraction of the budget, the television version is actually superior. Don't get me wrong, I actually like the Hammer version (even with the numerous liberties they took) but this version truly is superior.
Sign is the most accurate version I have seen outside of the version starring Ian Richardson.
This version of Carbuncle was superior to the Brett version, in my opinion, with the sole exception that the Brett version was cast slightly better in a few roles. Unlike the Doyle story, this version fixes the open ending wherein the innocent man remains in jail.
A Study in Scarlet is, to my knowledge, the only actual version filmed to date (the Reginald Owen uses the name only, the story is completely new) and it is as faithful as one could be with a 50 minute running time. The beginning of the novel is ignored as Holmes and Watson already live together at this point in the series (ironically, the Ronald Howard/H. Marion Crawford television series used only the beginning in "The Case of the Cunningham Heritage" and then created a whole new mystery to follow).
Boscombe is, like Scarlet, about as accurate as one could be within the 50 minute running time.
Frankly, I found Cushing's interpretation of Holmes to be the most accurate I have had the pleasure of viewing (Yes...while I realize it is sacrilege, I actually prefer him to Brett!) but I will allow I have not seen any of the Wilmer series.
I would rate this DVD set a full five pathetically drawn meerschaum pipes.