Hi - I'm not sure if the following will help (you and/or others), but I have been thinking of moving to North Yorkshire and one of the things I searched for was a good independent Honda specialist for when my 5-year Honda service plan runs out. It seems that they are very thin on the ground (not just in Yorkshire, but all over the UK) and hence why it is difficult to find them.
However, I did come across two that are in your general neck of the woods (although not precisely in the areas you specified):-
1) PCH Automotive Solutions - Unit 3, Levens Road, Newby Road Ind Estate, Hazel Grove, Stockport, SK7 5DL - 0161 425 1067 - they have a lot of excellent Google reviews and comments on their website.
https://www.pchautomotivesolutions.co.uk/2) KDN Honda Works - Unit 2, Knowle Spring Brewery Industrial Estate, Keighley, BD21 1AQ - 01535 609831 - they don't appear to have a webpage, but have excellent reviews on Google.
Please note that I haven't used them myself or know anybody who has - I'm just going off their online reviews which are excellent.