I have used them before - I bought my K10D and various other bits (tripod, filters, s/hand lens) from them. Like SRS they have a shop (in this case just off the M25/A10 junction) and you need to quote web prices as the in-shop prices are higher than the web prices.

They have been pretty good so far - no complaints. Sadly the staff change regularly. However, they are a Pentax Pro Centre.

The 12-24 has revolutionised my photography. It also taught me a few things:

I had to think harder about composition at wide angle.
Focus then recompose is very dangerous at wide angle.
The angle of the camera to the subject is very important(two examples being - faces at the edge of the image can seem distorted - keeping parallel lines parallel, such as walls when shooting inside).

Parden me for posting this if it seems obvious to the experts, but I hope this might help!

I have been amazed by the quality of what I've produced with this lens.

That's amazing. They also offer a trade-in on GX10, which would be interesting for me (as I have a Pentax K10D but my daughter has the GX10). However, even thought they are supposed to be open this afternoon, they don't answer the 'phone.

Well, the initial figures were £99 and £175 as quoted by Mike-P, hence my question. So, yes, on that evidence it would seem that Ebayers get better deal.

What I learn from this is, that rather than believe the quoted web price I should first check to see if it's cheaper on Ebay.

I think John gets it right when he says "Now we are aware of the choice we can look into it and take advantage if we wish to."

Mine arrived (by cheque) less than 10 days after sending off.

I tried both at SRS (and they were very patient!).
As it was my birthday, my financial controller (and much loved wife ) allowed me to spend the extra and buy the Pentax 12-24. IMHO it's a much nicer lens than the Sigma - more compact and better built (I'm not experienced enough yet to comment on the optics, but pics I have taken with this lens have amazed me, especialy compared to the kit 18-55mm at similar zoom setting). However, I have to say that for the money the Sigma would seem to be really very good. Hope this little personal reflection helps.

This disparity between SRS web and Ebay pricing could be a source of irritation... I don't use Ebay, so did I pay too much last time?

Edit - I'm not trying to wind anyone up here - this is a serious question. Maybe I need to get an Ebay account and 'play the system'? I like SRS because they are competitive and give good service. I'd be disappointed to learn that Ebayers get a better deal out of SRS than web/shop purchasers.

Me too. This lens is amazing!

Henley-on-Thames.
Just a suggestion. Some nice photo ops.

I've visited both SRS shops - the one in Rayners Lane is like a museum, with lots of second-hand and obsolete imaging stuff lying around (fascinating!) and top notch staff. The shop in Watford also keeps second-hand, etc. and again, helpful staff. Both sell printer supplies and all the other bits and pieces, like bags and filters.
The Watford shop keeps a very good supply of new Pentax equipment in stock, and is therefore recommended if one is not sure what one wants (re: my wide angle lens dilemma).
They just delivered my new Tamrac bag (bought by some friends for my birthday)!
While not the cheapest for everything (e.g. filters and Epson cartridges) IMHO they are worth a little extra for peace of mind.