My box has no brand name, just DVB-S2. I bought it on AliExpress. I think I just picked the cheapest one. Don't remember exactly what it cost, but it wasn't much. It has worked perfectly for several years though I don't use it much.

I think modern Sky dishes are around 60 cm. I don't know if that is sufficient for IS19. I believe early ones were bigger, some as much as 90 cm. I have measured mine and it is 80 cm. It may have been a one-off, from the installer's private stock. 

A friend with proper equipment installed the D2 LNB for me, but I did the IS 19 one myself. I took the receiver up to where the dish was and used my laptop with an Easycap digitiser to view the signal. I set the receiver to a known IS 19 transponder I got from Lyngsat and just held the LNB in my hand and moved it around until I got a signal. I estimated the position by eye and fabricated a bracket with some bits of plastic, which I added to the existing bracket. I then fine-tuned the position while watching the image on the laptop. I don't remember having to adjust the skew at all. Maybe I was just lucky. It is still working fine after several years. If you are into experimenting, you may also be lucky. I remember at the time I was surprised how easy it was. I watched bits of Nine on and off while it was on D1 and later also on IS19. I have never had any problem receiving it.