Watergate - Frigate* * - other ships are undoubtedly available, but Nick is better placed than I am to comment..
Once upon a time we had lots of warships now we have about 10 and the new state of the art destroyers have got engines & power generation systems that are not fit for purpose and will have to be replaced !! NOT like replacing spark plugs Frigate - Delegated
Irrigated. Agate ** ** Other varieties of crptocrystilline silica are available, although ( arguably) none are so useful and attractive as bookends
Elongate - Billingsgate* * - is one of the 25 Wards of the City if London. Its name derives from being the City's original water gate, and this small City Ward is situated on the north bank of the River Thames between London Bridge and Tower Bridge in the south-east of the Swquare Mile.
All work and no play mate. Never mind onwards and upwards. Next theme is words containing double ll billingsgate pollutants