Thanks for the clarification on the "buildfix" differences. The stuff that was on the shelf in my branch was the "proper" Mapei product
http://www.mapei.com/GB-EN/product-detail.asp?IDMacroLinea=0&IDProdotto=76&IDTipo=1611&IDLinea=1 with no buildfix branding at all but for the same price as the "buildfix" so I'm not complaining. I note that the Mapei Rapdset I used and also the Buildfix version are both classified C1F whereas Keraquick is classified C2FT so is no doubt a better product as class 2 designates "improved" but class 1 is just "normal" and the T means it is also non-slip so the absense of a T on the C1F presumably means it isn't (but slip wasn't a problem for me)
I found this which might help those who are confused understand the classifications:
Classifications of Tile Adhesives
Tile adhesives fall into three categories: Type C (Cementitious); Type D (Dispersion) and Type R (Reaction Resin). Here are some of the b
(Type C) Cement-based Adhesives
Cement-based adhesives come in the form of dry powders that are mixed with water. Once set, they are usually unaffected by water so are often a good option for use in wet environments. If you want to color your adhesive (for example if you are not using grout) then you can buy a powder colorant for use BEFORE you add water to the adhesive. You can also buy liquid colorants for use after you've hydrated the adhesive. Some cementitious adhesives can be mixed with additives to give them extra properties like more strength or greater flexibility, etc.
(Type D) Combined Adhesive and Grout
For the experienced, using an adhesive/grout combination is rarely advisable except for the smallest and simplest of jobs. Inevitably you need to make　compromises if you choose this option, as what is desirable from a grout is not necessarily a wanted property in an adhesive - and vice versa. It does have the advantage of being incredibly easy to use however; so consider it if this is your first tiling adventure and the job isn't too ambitious.
(Type D) Acrylic or PVA-based Adhesives
These are premixed adhesives. They are by far the most common adhesives for wall tiling, as it's easy to use, and also to clean up should there be any spillages. They set by drying naturally through water loss. Avoid using this kind of adhesive anywhere where there will be a lot of moisture or unusual heat.
You can also buy water-resistant (which is not to say "water-proof") varieties of PVA-based adhesives for non-commercial use in bathrooms and showers.
(Type R) 2-Part Resin Adhesives
These come in two parts, to be mixed by the tiler on site.　One part is the resin while the other is a hardener. If you did not already know this, then you should probably not pursue this option, as two-part-resin adhesives are usually difficult to use and expensive to buy. Even for experienced tilers, this is an option typically reserved for particularly difficult situations or very specific needs.
Vinyl Tile Adhesive
If you are using vinyl tiles then the previous information may be of limited use for you. The tiles are likely to be self-adhesive, in which case you should not need to use anything extra. If they are not, and of course you should check before you buy, then purchase some vinyl tile adhesive (specifically for floors, if this is what you are using them for). It sets fairly quickly and is of course very sticky, so if you mess up a tile, be ready to whip it back up quickly!
Other Tile Adhesive Classifications
In addition to the types laid out above, extra characteristics are also described by these numbers and letters:
1: normal adhesive
2: improved adhesive
F: fast-setting
T: adhesive with reduced slip
E: extended open time (cementitious adhesives and improved dispersion adhesives only).
For example, and adhesive labelled D2F would be a fast-setting dispersion adhesive with improved adhesive properties. Memorizing these will certainly make it seem that you mean business when you speak with your supplier.
In case you were wondering, "open time" is the maximum space of time after an adhesive is applied, at which tiles can be embedded in the adhesive and still meet the stated bond strength requirements.
This information should help you clarify what you are looking for before you choose an adhesive. Without the right adhesive, your tiling project is doomed to failure so, while choosing the tiles may be more interesting and fun, the adhesive choice is, if anything, even more crucial.
