Access to Frost Control/Drain Valve

Under the offside Settee Bed there are two access holes to get to Frost Control/Drain Valve, I require two blank plastic caps to cover these, about 80mm Dia. does anyone know where I can get these, colour not a problem but white or cream preferred. Thank You
Peter

Something like this?

https://www.ebay.co.uk/itm/123893523092?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20201210111452%26meid%3D2a248f3fb36e4abf977eb295ff476b15%26pid%3D101196%26rk%3D5%26rkt%3D11%26sd%3D283992618502%26itm%3D123893523092%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithBBEV2bAndUBSourceDemotionWithUltimatelyBoughtOfCoviewV1%26brand%3DUnbranded&_trksid=p2047675.c101196.m2219&amdata=cksum%3A1238935230922a248f3fb36e4abf977eb295ff476b15%7Cenc%3AAQAGAAACMM9k3DMwwBvpMlxi%252Bkq%252FDWzxk2DVWN95GBom%252FBu9iZxNkCFXGqP2qrSuxotEGXk0r3vSOrVuvFKzntGUzWemxzxx3butUpzOrhV5rDh6EEN1PLcXLqSlSprE8H6ZtL9mDkr0R93e4%252Fd%252Bm2IN69ttAmZz3%252FhekuxsmRWg04CnCaB%252BhKbNs0M2XjyFLMEYKM%252FZBMHNflTBerHoSP6gsn9FVu9wCbtwfASXjghp3xT6FApDFy17WCuGHO%252FSGSjMloX8Hf63S4SVIgyYJIXgRvI8S4mtRDKSVN5gA296zmzV1HGoNqcKXuw1gJ2LbKNvLT2H%252BuLSoV3IskT712PPZP4kO%252B3FOdaQ3GfQsKAERwlS7RPBJWLrFq029m9GeHTVsk3dywdkvNkVlQ5fvQLNU8BMMv2m%252FgkDh4IsB84pR0OECsvaL%252B4Iee9gdlMuGTUWZTmMj02v%252FU%252BUnzXDFQiFvLc%252BUYcm0tkROIFJ1oSRbLPrZxaOcraAdNTeWpjrx239pCP14ZxVo1tTU1ksnEnqVKaWAPpW7DUBYYFipPwBsq9w8hkzKNAGEUPuhux8WKrM7Eki45HRYQ5Tz%252F2WgPfRoxMcntzY44A9MbLfUtd0sZDPfa1tgUWPOx9n2I9Jmz8%252BRoe%252B5WlB67CpGJoZ32S68UJipHVCKt3fpE10b9%252FF2GuqdNuCVfh6wUK5Q65FxIdVEbWkxI65FAC4pXUVcOpGddo%252FrYAelVK5pUGx9JY6AFzsKe5k%7Campid%3APL_CLK%7Cclp%3A2047675

Thank You PLoughlin, The ones in use look like stay fresh lids used on dog food etc but the ones I need are 80mm, the ones on ebay could fit the purpose but need to b cut down a bit.
Thank You for your help
Peter C