Possibly inputted some information incorrectly or some disconnect with the information they have registered. That's all I had. No problems at all when turned up in person

I appreciate why people go this route (and there but by the grace of the great spaghetti monster etc.) but just pointing out that there are potentially quite serious consequences if they get caught out (and hence explains why the costs of going down this route are so high)

Your friend is lucky they weren't blacklisted and deported for fraudulent paperwork so could have been worse

I recall seeing a requirement for 10 working days before due date for postal applications

Proper planning prevents piss poor performance

If people aren't lawyers, I would take any advice they give with a pinch of salt (a bit like the earlier poster who said that 10 year visas weren't possible simply because they had never heard of it). Very few understand the actual requirements, and whilst many do get visas without extensive documentation, this will make the process into more of a lottery than it need be. If you are familiar with the old military phrase PPPPPP then it is well adhered to

It isn't a particularly difficult process but it does need some planning and some time expended on it in order to ensure the best chance of success

Any Thai documentation provided such as Blue House Book Baan, Chanote, Vehicle Blue Book etc. should be translated into English. Don't provide documentation and expect it to be translated by VFS in Thailand. They won't do it, and no translation means that the document is unlikely to be accepted

VFS simply process the documentation. Beyond checking all the boxes in the application are completed, and compiling the documentation supporting the application, they have no actual involvement in the visa issuing process, which is always done by a UKBA ECO (Entry Clearance Officer) either in-station (BKK) or in UK

Unless you are very confident with dealing with the documentation required, I would recommend that you have a lawyer or visa professional assist you with the process. A lot of people are rejected because they fail to provide sufficient documentation etc. You should be prepared to provide a covering letter with quite a lot of detail about your relationship with your wife, her family, your family, your life together and purpose to visit UK, how you/she will be supported during that time, and why she should return to Thailand (previous visits is always a good indicator etc.). Some may argue that this isn't or shouldn't be necessary, but my recommendation would always be for too much rather than too little. Supporting documentation should be as extensive as possible and if possible letters and supporting documentation, photos etc. from family in UK