Its sad to be reading review like this (from @itsuki), but considering many of us from the UK have used Tuning Developments multiple times I feel compelled to chip in too.
I have used them many times (first NA, then TD Turbo kit), and in fact all my major mods have been done or installed by Mike's team ( @Mike@TD.co.uk). Never had any issues and the service was always superb (had a manifold blow once, Mike fitted me basically next day and got it sorted pronto). Admittedly, I would go to Warrington myself and speak to Mike as to what I want/ what options are available, etc.
I am not surprised reading "horror stories" about shipping recently. We have covid, brexit and particularly over November-December I had parcels lost, delivered 3-4 weeks later, etc (for example my new wheels were delayed, and then DHL notification arrived a week after the wheels themselves - go figure).
Large number of satisfied customers hopefully will back me up with their 1st hand experience, although there would be an occasional story with unhappy ending (as I have heard with forged engine) - like with any business. Limited Google or FB reviews are not (probably) the representative sample, although anyone who feels they have to leave a 1* review should be listened to by the business aiming to improve their customer service.
I hope with the move to new premises and increase of business Mike will also get someone to help with the customer service/ tracking shipping/ other admin and client communication stuff.