From the description you have given me so far I am able to tell you the following:
Pattern: 28586 (Silverplate, Hollowware) by Walker & Hall
Pattern Number: 28586
Description: Silverplate, Hollowware, Gadroon, Shell
The business was established in Sheffield in 1845 by ***** *****. Becoming an assistant of Dr. ***** ***** who had conducted important experiments on electroplating Walker secured the royalty of electroplating for Sheffield. The business was joined by ***** ***** and became in 1853 Walker & Hall. The factory was at Howard Street, Sheffield, while showrooms were opened in 45 Holborn Viaduct, London. Branches were opened in Liverpool, Manchester, Leeds, Glasgow, Edinburgh,Newcastle, Cardiff, Belfast, Hull, Bristol, Melbourne and Adelaide (Australia), Cape Town (South Africa). Walker & Hall was converted into a limited liability company in 1920 under the style Walker & Hall Ltd and combined in 1963 under the British Silverware Ltd with Mappin & Webb and Elkington & Co. Walker and Hall Sheffield were primarily Sheffield Makers, but items with Birmingham, London and Chester Assay Marks can also be found.
I will be able to date and value the tray once I can see the markings. Thank you and I look forward to finishing this for you.