Matt,
Your first line still troubles me because as a salesman it just does not sell you & the products you are selling??? Yes, you are trying to say HQ can equate to lower prices than expected to that level of HQ ~ but family photography surely is selling a perception/dream/aspiration/captured moment in time....?
You said
Here at Matt Peters Photography we aim to deliver the highest quality photography while still retaining value for money!
Can I suggest:-
At Matt Peters Photography our aim is to provide the best value photography service delivering photographic memories of the highest quality that you will treasure for many years to come.
This does not follow the rule "you", "we", "I" but in a single strapline that is hard but I have underlined the key 'trap' words that should subconsciously attract. NB the underlining is only to emphasis my rewording ~ not to be left like that in any final copy 
Also can I clarify will you always 'speak' in the third person as in if you do not do the shoot who will you appoint. A nitpick for sure but MPP is just you and IMO you should be proud of the fact and yes punch above your weight but to give the impression you are a team just possibly could be seen as misleading???
You have shown the quality you can provide which the other guys who do more of that sort of togging have complimented you on/about so do not sell yourself short 