Seems to me like you want to have your cake and eat it!
You say you bought this share because it was 'cheap as chips flying' but you haven't felt like flying there. You also mention that you are more used to (=prefer?) bigger airfields and hard runways. All the more reason then to ensure that you are checked as proficient to operate in and out of what you describe as "a relatively small grass airfield". I would have thought your own sense of self preservation would make you want to ensure you are confident that you will not end up hanging upside down from your straps in the hedge, especially as your inference is that you have less than 50 hours P1 or you would be looking at a 28-day interval.
If it's cheap as chips, then what's putting you off doing the necessary checks if you are not flying within 21 days? You knew the rules when you bought the share. Either comply with them or get rid of the share!