I've seen you around here and there for years. So you must be doing something to stay in business. A lot of people really want plug and play with assurance. But they need to be willing to pay. Some people are simply looking for a source for getting a Tdi and they are willing to fix it if it needs it. But I think most people are someplace in between.
Just from looking at your offerings and your web site, you seem to be catering to people who just want a Tdi in running condition that they can put into their non-refurbished Defenders.
And there really isn't anything wrong with that, just as long as that is what is presented, you have good pricing, and you deliver exactly what you say you are selling.
So the second part of that equation can only be validated by references. Having a reference page would be good. But in these types of online communities, especially the Rover ones, you really should have people on these forums who can vouch for your service who are at least partially contributing to the community as well. That's the way it is.
That said, I do hope you do well! And I'd like to see you as a contributor to this site. And I'd like to see others here happily getting engines from you.