LAA = Light Aircraft Association, formerly known as the Popular Flying Association. An LAA aircraft is a sub-ICAO aeroplane, certified for operation in the UK by the LAA. The organisation has a similar, but not identical, role to EAA in the USA. Pretty much anything that in other countries would be "Experimental" or "Homebuilt" along with a lot of simpler vintage aeroplanes - although not the majority of microlights (2 seaters up to 450kg MTOW and single seaters up to 300kg in the UK) come under LAA.
The rules require that they have approved operators manuals, in many cases however they don't because LAA don't think this is necessary. I believe that, in this regard, LAA is wrong. To be fair, their policy on this does seem to have changed in the last couple of years; I tested a vintage aeroplane for them last year, and the approach taken to operating data was very thorough.
LAA do, to be fair, publish a set of operating limits which must be placarded. These might, on the other hand, have more credibility, if they ever determined the PECs for their aircraft which, in the vast majority of cases, they don't. In this regard, I also think that LAA is wrong; their policy on this doesn't seem to have changed that I'm aware of.
ProfChrisReed is incorrect in stating that Vne is declared in TAS; it is, like most other V speeds, normally declared in IAS. However, if it is determined by flutter onset, then this is a function of TAS, for which reason it may be necessary in some aeroplanes to vary Vne with altitude. This isn't however often done, in which regard, I think that many of the engineers certifying gliders are probably also wrong.
G