G Techniq is one of the best products out there at the moment, but it can be a cow to apply, especially on dark metallic paint colours, thats why most Detailers charge a premium, plus if they do it right they will need it for 2 days, as the first coat needs to be left for 12 hrs at least to cure.
If you are competent and want to do it yourself, then the Carlack Twins are 2 good products, they are nano based synthetic waxes. The first is a paint cleanser and really a base for the following top coat gloss application. You will get a good 3 to 4 months protection before needing to re-apply another coat.
All available from Cleanyourcar in Huddersfield - speak to Tim for info, he will help you out.