Rustproofing companies

I want to get my 2006 Defender rustproofed/waxoyled

It was done a few years ago for £150 but they just sprayed it all over the place and now there's surface rust under the waxoyl in places

"Rustmaster" just got a glowing review in LRO and also did one of their Land Rovers, the cost is £600 but they promise to clean the chassis first and inject the bulkhead/chassis/doors etc with special "professional" waxoyl
And they have a branch in Knutsford, Cheshire which is near to me

There's also an outfit near me called "Chassis clean" who promise the same job, again for about £600 on a Defender
They are based in Altrincham, Cheshire

So, has anybody used either of these companies, and can they be recommended to do a job that's worth £600?

Compressor £150, waxoyl £30, self satisfaction - priceless.

Don't think it would be too hard to do. I've just hand painted the chassis I can get to with tractol and waxoyl what I can't paint.

I think there's a place in Coventry area that does it, from memory 4 or£500 quid, can't remember the name though sorry