Look man there's no good way of telling you this, but that list is gonna get absolutely mauled :(
in combat patrol settings you can expect to run into new players/players new to that particular army, and right now your force kinda looks like it'd struggle to get free of a wet paper bag... god forbid you run into a death guard player...
first the good stuff!
-3 sentinels is some serious staying power, and at this point level thats exactly what you want em doing, staying back, holding objectives with their durability and scoring you some points. admittedly most players will struggle to kill those sentinels with their own 500pts of firepower, but its not uncommon to see heavy weapons in various infantry squads in combat patrol... and if an opponent knows the list you're laying down... lets just say you're not gonna have a great game.
good number of bodies (more on that later)
good choice of relic/warlord trait... not the best, but good choice.
my main issues with your list are centered around the lack of high strength ranged weapons... or in fact anything longer range than a lasgun...
consider running tallarn regiment, for 3 CP
you can "ambush" 3 units... (2 sents, 1 sent, bullgryns), which may make them more threatening considering their range limitations if you're married to the flamers...
infantry squads without a heavy/special weapon in larger games are the go-to, cheap non-offensive units to screen/ignore on an objective. in combat patrol theyre gonna be lacking firepower considering they make up a considerable chunk of your overall force. if you have or can get plasma, grab it. I say this because its high strength is enough to damage infantry and the sorts of light vehicles you can expect to have problems with at 500pts (especially if overcharged for the emperor!)
honestly i'm not sure how effective the bullgryns will be at such a low points value, their cost kinda needs a big juicy target to pummel in order to get those points back and turn a profit, which you may struggle to find at 500pts.
I would personally try a re-write dropping the bullgryns, and getting missile launchers/plasma cannons on those sentinels. maybe grab some plasma for those troops, and consider other lower points units that will cause a problem.
for example: a company command squad of 4 veterans with sniper rifles/ratlings to pick at the enemies force multiplying characters.
a special weapons squad with flamers if you're expecting hordes?
that said, I like winning, and your patrol is really fluffy
-please hit me up if you'd like to discuss it further, Guard have a strange amount of options at 500pts, so its just about playing around until you find what works for you.
take all advice with a pinch of salt, I'm no expert, just a guy with a small regiment of Kasrkin
Hope this helps,